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Anti-nucleocapsid SARS-CoV-2 antibody seroprevalence in previously infected persons with immunocompromising conditions-United States, 2020-2022
Bratcher A , Jones JM , Meyer WA 3rd , Waheed R , Yazgi H , Harris A , Gundlapalli AV , Clarke KEN . PLoS One 2025 20 (1) e0313620 People with immunocompromising conditions (IC) are at increased risk of severe COVID-19 and death. These individuals show weaker immunogenicity following vaccination than individuals without IC, yet immunogenicity after SARS-CoV-2 infection is poorly understood. To address this gap, the presence of infection-induced antibodies in sera following a positive COVID-19 test result was compared between patients with and without IC. A commercial laboratory provided patient data gathered during July 2020-February 2022 on COVID-19 viral test results and antibody assay results, which included infection-induced (anti-N) antibody presence. Participants were categorized into having or not having IC based on if there was an indicative diagnostic code on their health record for a five-year period prior to the study period. Anti-N presence in sera from people with a positive COVID-19 test result was compared by IC status for four post-infection periods: 14-90, 91-180, 181-365, and 365+ days. A longitudinal, logistic regression produced adjusted odds ratios comparing anti-N prevalence among specimens with and without associated IC, adjusted for age, sex, residence in a metro area, and social vulnerability index (SVI) tertile. Data included 17,025 anti-N test results from 14,690 patients, 1,424 (9.7%) of which had at least one IC on record. In an adjusted comparison to patients without IC, patients with any IC were 0.61 times as likely to have infection-induced antibodies (99% CI: 0.40-0.93), during the 14-90 days following infection. Similar patterns were found when comparing people with two specific types of IC to people without any IC: (1) solid malignancies and (2) other intrinsic immune conditions. These findings stress the importance of prevention measures for people with IC, such as additional vaccination doses and consistent mask use before and after a documented infection. |
A retrospective evaluation of pandemic policy impact on university campus: An agent-based modeling approach for mobility, disease propagation, and testing during COVID-19
Chen Y , Islam MT , Jain S , Barua Chowdhury BD , Son YJ . Expert Sys Appl 2025 266 In the fight against the spread of infectious disease, university campuses present a unique set of obstacles because of the prevalence of communal living arrangements and the difficulties of restricting sociability and group gatherings. In the last few years, the dynamics of the pandemic have evolved, and so too have the challenges university campuses face in ensuring their communities’ health and safety. This study introduces a complex and adaptable hybrid model, which was developed, applied, and validated using data from the peak incidents of SARS-CoV-2 during 2020–2021. It combines an agent-based model (ABM) with a modified SEIR system dynamics approach. Recognizing the shifting landscape of the pandemic, this model has been designed to function as both a historical case study of COVID-19 dynamics on a university campus and a framework for addressing future pandemic threats. By simulating disease propagation considering contact distance (i.e., 0–3 feet, 3–6 feet), contact duration (e.g., indoor layout, capacity, ventilation), and individual behaviors (e.g., partying, gathering, sporting, off-campus activities), the model serves as a comprehensive analysis tool. It incorporates GIS-based campus data, real-time Wi-Fi occupancy data, student schedule-based behavioral patterns to closely emulate campus life. The testing frequency (e.g., mandatory, voluntary), methods (e.g., PCR, antigen, antibody, saline gargle, saliva), and different containment policies (e.g., mask-wearing, vaccination) enhance the model's predictive capabilities. The model's flexible structure allows stakeholders to adapt it to current and emerging scenarios. Retrospective analyses indicate that strategies like indoor mask mandates, frequent testing, and high vaccination rates were pivotal in managing spread of disease. The model's predictive accuracy, as evidenced by high accurate rate (i.e., 85.1% accuracy with an average deviation of 4.42 cases per day) when comparing the model output to actual campus data, underscores its value as a decision-making aid for university administrators in the ongoing efforts to foster a resilient and healthy campus environment. © 2024 Elsevier Ltd |
Lessons learned in establishing and sustaining elastomeric half mask respirator-based respiratory protection programs: An impact evaluation
Haas EJ , Edirisooriya M . J Occup Environ Hyg 2024 1-11 Developing and overseeing Respiratory Protection Programs (RPPs) is crucial for ensuring effective respirator use among employees. To date, a gap exists in research that focuses on elastomeric half mask respirators (EHMRs) as the primary respirator in health delivery settings which would necessitate additional considerations in RPPs beyond the more common N95 filtering facepiece respirators. This paper presents lessons learned during a one-year impact evaluation with healthcare and first responder settings that received EHMRs from the Strategic National Stockpile in 2021 and 2022. The study explored the advantages and disadvantages associated with EHMRs and the challenges related to establishing, implementing, maintaining, and sustaining EHMR-based RPPs. Data was received from 42 organizations that participated in EHMR demonstration projects to address (1) the most important, perceived, elements and practices of an EHMR-based RPP to support a long-term program; and (2) differences in perceptions of the most important elements and practices based on organizational and company size (i.e., small, medium, and large). Sustaining an EHMR program was considered the most important area to focus future efforts (M = 2.94; SD = 1.12 on a 4-point scale), followed by daily maintenance of the program (M = 2.72; SD = 0.974), development and implementation of the program (M = 2.42; SD = 1.05), and access to EHMRs (M = 1.91; SD = 1.11), respectively. Findings also revealed statistically significant differences in perceptions based on organization size, particularly in access to EHMR models/designs. Results underscored the significance of user accountability, organizational support, and culture in EHMR-based RPPs to support emergency preparedness efforts. |
Evaluating source control efficacy against exhaled submicron particles: Total outward leakage of surgical masks and half facepiece respirators across a spectrum of particle sizes
Yang W , Myers WR , Bergman M , Fisher E , Ryan KJ , Vollmer B , Portnoff L , Zhuang Z . Aerosol Sci Technol 2024 The size of airborne particles emitted from infected individuals is crucial in the transmission of respiratory viruses. The use of source control devices is essential for interrupting the transmission of exhaled submicron particles, particularly in healthcare settings with high infection risk. This study evaluated the efficacy of five types of source control devices, commonly used in healthcare settings, in mitigating the transmission of exhaled submicron particles (20–210 nm). Total outward leakage (TOL) of these devices was analyzed across different particle sizes, and the TOL mean diameter (TOLMD) was calculated to characterize particle size distribution. The devices tested included N95 filtering facepiece respirators (N95 FFRs), N95 FFRs with an exhalation valve (N95 FFRV), surgical masks (SMs), elastomeric half-mask respirators (EHMRs), and EHMRs with a SM covering the exhalation valve (EHMRSM). The study also examined the effects of faceseal and flowrate on TOL and particle size characteristics. Results indicated that TOL varied with particle size, increasing from 40 to 90 nm before stabilizing. Aerosols larger than 90 nm had significantly higher TOL compared to smaller aerosols. Higher flow rates increased TOL for EHMR and EHMRSM across all particle sizes. Improved faceseal on N95 FFRs and SMs significantly reduced TOL and decreased TOLMD. The study underscored that using well-fitting devices without exhalation valves is crucial for preventing the transmission of exhaled aerosols potentially carrying viruses, in particular for larger particle sizes. This is especially crucial in the absence of proper indoor ventilation and other control measures. © This work was authored as part of the Contributor’s official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law. |
Epidemiology and response to the COVID-19 pandemic in the Dadaab Refugee Camp Complex, Kenya, March 2020-December 2022
Ope M , Musyoka R , Kosar A , Osman M , Hassan A , Mohammed H , Munyua P , Juma B , Hunsperger E , Mohammed S , Burton J , Eidex RB . Travel Med Infect Dis 2024 63 102785 INTRODUCTION: Refugee settings may increase the risk of SARS-CoV-2 infection and death, yet data on the response to the pandemic in these populations is scarce. METHODS: We describe interventions to mitigate SARS-CoV-2 transmission in Dadaab Refugee Camp Complex, Kenya and performed descriptive analyses using March 2020 to December 2022 data from Kenya's national SARS-CoV-2 repository and line list of positive cases maintained by United Nations High Commissioner for Refugees (UNHCR). We calculated case fatality rates (CFR) and attack rates per 100,000 (AR) using the 2019 national census and population statistics from UNHCR and compared them to national figures. RESULTS: SARS-CoV-2 infection was first reported in April and May 2020, among host community members and refugees respectively. Of 964 laboratory-confirmed cases, 700 (72.6 %) were refugees. The AR was 82.7 (95 % CI 72.6-92.8) for host community members, 228.3 (95 % CI 211.3-245.4) for refugees and 721.1 (95 % CI 718.7-723.5) nationally. The CFR was 1.5 % (95 % CI 0.15-3.18) for host community members, 1.76 % (95 % CI 1.71-1.80) nationally and 7.4 % (95 % CI 5.4-9.4) for refugees. Mitigation measures implemented by the Government of Kenya, UNHCR and partners during the pandemic included multisectoral coordination, movement restrictions, mass gathering bans, and health promotion. Social distancing, symptom screening and mandatory mask usage were enforced during mass gatherings. Testing capacity was bolstered, quarantine and isolation facilities established, and vaccination initiated. CONCLUSIONS: Despite a low AR and UNHCR's swift and comprehensive response, refugees' CFR was high, underscoring their vulnerability and need for targeted interventions during epidemic responses. |
Wipe disinfection of reusable elastomeric half-mask respirators for health care use
Erukunuakpor K , Nielsen KE , Lane MA , Hornbeck A , McClain C , Fernando R , Sietsema M , Kraft CS , Casanova LM . Workplace Health Saf 2024 21650799241273972 BACKGROUND: During shortages, elastomeric half-mask respirators (EHMRs) are an alternative to reusing N95 filtering facepiece respirators but require between-use disinfection. The objectives of this study were to (a) measure microbial reductions on EHMR surfaces under laboratory conditions by a standardized procedure using wipes impregnated with health care disinfectants and to (b) measure microbial reductions on EHMRs disinfected by volunteer health care providers. METHOD: We inoculated EHMR (Honeywell model RU8500) surfaces with Pseudomonas aeruginosa, Bacillus atrophaeus spores, and bacteriophages MS2 and Φ6, and disinfected them using two wipes with hydrogen peroxide (HP), alcohols, and quaternary ammonium compounds (QACs). Then, we randomized 54 volunteer subjects into three groups (Group 1: two wipes with instructions, Group 2: five wipes with instructions, Group 3: no instructions or set number of wipes) and used 0.5% HP wipes without precleaning on EHMRs inoculated with Raoultella terrigena and MS2. FINDINGS: The laboratory study demonstrated that all organisms achieved at least 4 log(10) median reductions (HP>QAC/alcohol>QAC>QAC/saline). Pseudomonas was highly susceptible to HP and QAC/alcohol and Φ6 to all disinfectants. MS2 reduction was highest using HP and lowest using QAC/saline. Bacillus was least susceptible. The volunteer study showed a 3 to 4 log(10) average reductions of bacteria and virus; Raoultella reductions were greater than MS2, with variability within and between subjects. Conclusions: HP disinfectant wipes used in laboratory and by volunteers reduce bacteria and viruses on EHMRs by 3 to 4 log(10) on average. IMPLICATIONS FOR PRACTICE: Commercially available hospital disinfectant wipes reduce bacteria and viruses on EHMRs and can fill the need for between-use disinfection. HP and combination QAC/alcohol have the greatest efficacy under our test conditions. |
Changes in self-reported mask use after the lifting of state-issued mask mandates in 20 US States, February-June 2021
Ajiboye AS , Dunphy C , Vo L , Howard-Williams M , Ladva CN , Robinson SJ , McCord R , Gakh M , Weber R , Sunshine G . J Public Health Manag Pract 2024 OBJECTIVE: In April 2020, the US Centers for Disease Control and Prevention (CDC) recommended community masking to prevent the transmission of SARS-CoV-2. Since then, a total of 39 US states and DC issued mask mandates. Despite CDC recommendations and supporting evidence that masking reduces COVID-19 community transmission, from January to June 20, 2021 states lifted their mask mandates for all individuals. This study examined the association between lifting state-issued mask mandates and mask-wearing behavior in 2021. DESIGN: We estimated a difference-in-difference model, comparing changes in the likelihood for individuals to wear a mask in states that lifted their mask mandate relative to states that kept their mandates in place between February and June of 2021. SETTING: Individuals were surveyed from across the United States. PARTICIPANTS: We used masking behavior data collected by the Porter Novelli View 360 + national surveys (N = 3459), and data from state-issued mask mandates obtained by CDC and the University of Nevada, Las Vegas. MAIN OUTCOMES: The outcome variable of interest was self-reported mask use during the 30 days prior to the survey data collection. RESULTS: In the overall population, lifting mask mandates did not significantly influence mask-wearing behavior. Mask wearing did significantly decrease in response to the lifting of mask mandates among individuals living in rural counties and individuals who had not yet decided whether they would receive a COVID-19 vaccine. CONCLUSION: Policies around COVID-19 behavioral mitigation, specifically amongst those unsure about vaccination and in rural areas, may help reduce the transmission of COVID-19 and other respiratory viruses, especially in communities with low vaccination rates. |
School mask policies and SARS-CoV-2 seroprevalence among school-age children-United States, September to December 2021
Nycz E , Deng Y , Van Dyke ME , Bratcher A , Shi J , Iachan R , Berney K , Jones JM , Clarke KEN . Microbiol Spectr 2024 e0069124 During September to December 2021, school mask policies to mitigate SARS-CoV-2 transmission varied throughout the US. We compared infection-induced seroprevalence estimates and estimated seroconversion among children residing in areas with and without school mask requirements. We estimated infection-induced seroprevalence among children in three age groups (5-17, 5-11, and 12-17 years) in areas with and without school district mask requirements for two time points: September 1-30, 2021 and December 15, 2021 to January 14, 2022. Robust Poisson regression models estimated population seroconversion over the semester among initially seronegative children. Permutation tests assessed for significant differences in the estimated population seroconversion due to incident infections by school district mask policy. Residing in an area with no school mask requirement was associated with higher infection-induced seroprevalence among children aged 5-17 years (adjusted prevalence ratio [aPR] = 1.18, 95% confidence interval [CI]: 1.10, 1.26), and those aged 5-11 years (aPR) = 1.21, 95% CI: 1.10, 1.32) and those aged 12-17 years (aPR = 1.16, 95% CI: 1.07, 1.26), compared with areas requiring masks in school. Estimated population seroconversion during the semester was also significantly higher among children in districts without mask policies than those with school mask requirements among all age groups (5-17 years: 23.7% vs 18.1%, P < 0.001; 5-11 years: 6.4% vs 4.5%, P = 0.002;12-17 years: 27.2% vs 21.0%, P < 0.001). During the U.S. Fall 2021 semester, areas with school mask requirements had lower infection-induced seroprevalence and an estimated lower proportion of seroconversion due to incident infection among school-aged children compared with areas without school mask requirements; causality cannot necessarily be inferred from these associations. IMPORTANCE: During the U.S. Fall 2021 school semester, the estimated proportion of previously uninfected school-aged children who experienced a first infection with SARS-CoV-2 was lower in areas where public school district policies required masks for all staff and students compared with areas where the school districts had no mask requirements. Because children are more likely than adults to experience asymptomatic or mild SARS-CoV-2 infections, the presence of infection-induced antibodies is a more accurate measure of infection history than clinical testing. The proportion of children with these antibodies (i.e., seroprevalence) can improve our understanding of SARS-CoV-2 by detecting more infections and eliminating potential bias due to local testing and reporting practices. Enhanced robustness of surveillance for respiratory infections in children, including records of mitigation policies in communities and schools, as well as seroprevalence data, would establish a better evidence base for policy decisions and response measures during future respiratory outbreaks. |
Public willingness to mask and vaccinate in the future: Results from a 2023 nationally representative survey of US adults
SteelFisher GK , Findling MG , Caporello HL , Stein RI , Lubell KM , Fisher AM , Lane LA , Boyea A , Espino L , Sutton J . Health Secur 2024 22 (4) 311-323 The enduring spread of COVID-19 and other respiratory viruses highlights a need for greater focus on long-term public willingness to perform protective behaviors. Although COVID-19 is no longer considered a public health emergency of international concern, it is unknown whether people in the United States plan to continue protective behaviors to protect themselves and others against infection. To inform planning and communications, we used a nationally representative survey of 1,936 US adults to examine attitudes and intentions toward future vaccination and mask-wearing. A majority believed COVID-19 vaccines were safe (73%) and effective in protecting against serious illness (72%). One-third (33%) had strong intentions to get an updated COVID-19 vaccine most years in the future. Among those with weaker intentions (n=1,287), many cited concerns about safety (71%) and efficacy (64%), lack of trust in institutions (64%), or beliefs that prior vaccination or infection protected them (62%). Approximately two-thirds (69%) of respondents believed masks were effective in protecting the wearer from getting COVID-19, and a majority appeared moderately receptive to future public mask-wearing, particularly when there was proximate risk of infection from COVID-19 (67%) or other respiratory viruses (59%). Men, non-Hispanic White adults, younger adults, rural residents, and adults with higher incomes, without college degrees, and without serious medical conditions or physical limitations were more likely to indicate resistance toward future COVID-19 vaccination and/or mask-wearing. Findings support tailored messaging to address concerns and opportunities among different populations, as well as support for communications programs and community engagement to motivate future uptake. |
Experiences when using different EHMR models: Implications for different designs and meeting user expectations
Haas EJ , Edirisooryia M , Fernando R , McClain C , Sietsema M , Hornbeck A , Thurman P , Angelilli S , Waltenbaugh H , Chalikonda S , Hines SE . Am J Infect Control 2024 BACKGROUND: New elastomeric half mask respirator (EHMR) models without exhalation valves (EVs) or with exhalation valve filters (EVFs) are facilitating expanded use in health settings to reduce workers' exposure to airborne hazards while acting as source control to prevent pathogen spread. The physical comfort of new models has not been assessed in comparison to previously used EHMRs with EVs. METHODS: Researchers assessed 1,962 healthcare and emergency medical service personnels' self-reported adverse experiences from two cohorts while wearing EHMR models with EVs (Cohort 1, n=1,080) and without EVs or with EVFs (Cohort 2, n=882). Fisher's Exact Test identified differences between the cohorts accounting for organizational factors when possible. RESULTS: Cohort 1 respondents experienced communication challenges and discomfort when wearing the EHMR >1 hour statistically significantly more often than Cohort 2. Cohort 2 respondents reported statistically significantly more instances of difficulty breathing, moisture buildup, being uncomfortable to wear <1 hour, and being uncomfortably warm. CONCLUSIONS: Discomfort is prevalent among end users and more often among those wearing EHMRs without an EV/with an EVF. As EHMR research and development advances, prevalence in use may increase for emergency and routine situations. Organizations may not only need guidance about respirator selection but also model-specific selection. |
Efficacy of powered air purifying respirators (PAPRs) for source control of simulated respiratory aerosols
Lindsley WG , Blachere FM , Derk RC , Mnatsakanova A , Noti JD . Am J Infect Control 2024 BACKGROUND: Loose-fitting powered air purifying respirators (PAPRs) are a popular alternative to the use of filtering facepiece respirators for healthcare workers. Although PAPRs protect the wearer from aerosol particles, their ability to block infectious aerosol particles exhaled by the wearer from being released into the environment (called source control) is unclear. METHODS: The source control performance of four PAPRs with loose-fitting facepieces were tested using a manikin that exhales aerosol particles. The PAPRs were tested by themselves and in combination with a face-worn product intended to provide source control (either a surgical mask or an N95® filtering facepiece respirator.) RESULTS: Two PAPR facepieces with filtration panels significantly reduced the release of exhaled aerosols into the environment, while three facepieces without such panels did not. Wearing a surgical mask or respirator under the facepiece significantly improved the source control performance. CONCLUSIONS: Most PAPR facepieces do not block aerosols exhaled by the wearer. Facepieces designed to filter exhaled particles can prevent aerosols from being released into the environment. Wearing a surgical mask or a filtering facepiece respirator under the facepiece can also provide source control, but PAPRs are not typically certified for use with masks and respirators. |
Reusable respirators: the impact on safety climate across health settings
Haas EJ , Edirisooriya M , Furek A , Casey M . Prof Saf 2024 69 (5) 20-26 Key Takeaways: Receiving reusable respirators and corresponding ongoing communication and training may improve worker well-being, serving as a tangible indicator of organizational support. From an emergency preparedness standpoint, organizations may consider stockpiling reusable elastomeric half-mask respirators and updating their respiratory protection program (RPP) to include education about these respirators. From a health promotion standpoint, it may behoove organizations to develop comprehensive programs that emphasize management practices to increase worker perceptions of safety climate and, consequently, worker mental health and well-being. Supervisor or frontline leadership communication and engagement in the implementation of RPPs is critical to foster trust and adoption of new respirators. Ongoing role modeling and support by management to comply with the RPP or other safety and health plans are necessary to garner employee-wide participation in respiratory protection. |
The role of the environment: how mask wearing varies across different activities
Nestor C , Earle-Richardson G , Prue CE . BMC Public Health 2024 24 (1) 1561 BACKGROUND: People's decisions to engage in protective health behaviors, such as mask wearing during the COVID-19 pandemic, are influenced by environmental and social contexts. Previous research on mask wearing used a single question about general mask usage in public, which may not reflect actual behavior in every setting. The likelihood of wearing a mask during one activity is also related to the likelihood of wearing a mask in another or avoiding an activity entirely. This analysis compared responses between a general question and activity-specific questions and identified patterns of mask-wearing behavior across activities. METHODS: Online, opt-in, cross-sectional surveys were conducted every 2 months from November 2020 to May 2021 (n = 2508), with quota sampling and weighting to achieve a representative sample of the U.S. POPULATION: Respondents were asked how frequently they wore a mask in public and during 12 specific activities including: on public transportation, while shopping, and attending social gatherings indoors and outdoors. Spearman's rank order correlation was used to compare the frequency of mask wearing reported using a general question versus an activity specific question. Additionally, a latent class analysis was conducted to identify patterns of mask wearing behavior across activities. RESULTS: There was little to no correlation (r = .16-0.33) between respondents' general attitudes towards mask wearing and their reported frequency of mask wearing in different activities. Latent class analysis identified six distinct groups based on their mask wearing behaviors and avoidance of certain activities. The largest group (29%) avoided ten of the twelve activities and always wore a mask during activities that could not be avoided. Additional groups included those who avoided most activities but made exceptions when around friends or family (20%), part time mask wearers (18%), and never mask wearers (6%). CONCLUSIONS: The findings suggest that activity-specific questions provide more accurate and useful information than a single general question. Specific, context based, questions allow for analyses that consider the nuances of people's decision-making regarding engaging in protective health behaviors, such as mask wearing, thus enabling public health professionals to create targeted guidelines and messages. |
A longitudinal analysis of COVID-19 prevention strategies implemented among US K-12 public schools during the 2021-2022 school year
Conklin S , McConnell L , Murray C , Pampati S , Rasberry CN , Stephens R , Rose I , Barrios LC , Cramer NK , Lee S . Ann Epidemiol 2024 PURPOSE: Examine how school-based COVID-19 prevention strategy implementation varied over time, including by local characteristics. METHODS: School administrators (n=335) from a nationally representative sample of K-12 public schools completed four surveys assessing COVID-19 prevention strategies at two-month intervals between October 2021 and June 2022. We calculated weighted prevalence estimates by survey wave. Generalized estimating equations (GEE) were used to model longitudinal changes in strategy implementation, accounting for school and county covariates. RESULTS: Opening doors/windows, daily cleaning, and diagnostic testing were reported by ≥50% of schools at each survey wave. Several strategies were consistently implemented across the 2021-2022 school year (i.e., daily cleaning, opening doors and windows, diagnostic testing) while other strategies increased initially and then declined (i.e., contact tracing, screening testing, on-campus vaccination) or declined consistently throughout the school year (i.e., mask requirement, classroom distancing, quarantine). Although longitudinal changes in strategy implementation did not vary by school characteristics, strategy implementation varied by urban-rural classification and school level throughout the school year. CONCLUSIONS: Strategies that were consistently implemented throughout the school year were also reported by a majority of schools, speaking toward their feasibility for school-based infection control and prevention and potential utility in future public health emergencies. |
Cost-effectiveness of mask mandates on subways to prevent SARS-CoV-2 transmission in the United States
Park J , Joo H , Kim D , Mase S , Christensen D , Maskery BA . PLoS One 2024 19 (5) e0302199 BACKGROUND: Community-based mask wearing has been shown to reduce the transmission of SARS-CoV-2. However, few studies have conducted an economic evaluation of mask mandates, specifically in public transportation settings. This study evaluated the cost-effectiveness of implementing mask mandates for subway passengers in the United States by evaluating its potential to reduce COVID-19 transmission during subway travel. MATERIALS AND METHODS: We assessed the health impacts and costs of subway mask mandates compared to mask recommendations based on the number of infections that would occur during subway travel in the U.S. Using a combined box and Wells-Riley infection model, we estimated monthly infections, hospitalizations, and deaths averted under a mask mandate scenario as compared to a mask recommendation scenario. The analysis included costs of implementing mask mandates and COVID-19 treatment from a limited societal perspective. The cost-effectiveness (net cost per averted death) of mandates was estimated for three different periods based on dominant SARS-CoV-2 variants: Alpha, Beta, and Gamma (November 2020 to February 2021); Delta (July to October 2021); and early Omicron (January to March 2022). RESULTS: Compared with mask recommendations only, mask mandates were cost-effective across all periods, with costs per averted death less than a threshold of $11.4 million (ranging from cost-saving to $3 million per averted death). Additionally, mask mandates were more cost-effective during the early Omicron period than the other two periods and were cost saving in January 2022. Our findings showed that mandates remained cost-effective when accounting for uncertainties in input parameters (e.g., even if mandates only resulted in small increases in mask usage by subway ridership). CONCLUSIONS: The findings highlight the economic value of mask mandates on subways, particularly during high virus transmissibility periods, during the COVID-19 pandemic. This study may inform stakeholders on mask mandate decisions during future outbreaks of novel viral respiratory diseases. |
Seroprevalence of IgA and IgG against SARS-CoV-2 and risk factors in workers from public markets of Guatemala
Grajeda LM , Mendizábal-Cabrera R , Romero JC , López MR , Morales E , López B , Zielinski E , Cordón-Rosales C . COVID 2023 3 (9) 1416-1428 Public market workers may be disproportionally exposed to SARS-CoV-2 due to interactions with shoppers. We aimed to estimate the seroprevalence of SARS-CoV-2 and determine whether occupation or adherence to preventive practices were associated with exposure. From July to December 2021, we longitudinally surveyed two Guatemalan markets twice. We collected blood to detect anti-S IgA, anti-S IgG, and anti-N IgG using ELISA, and a nasopharyngeal swab to detect SARS-CoV-2 using rRT-PCR. We estimated seroprevalences and assessed associations using generalized estimating equations. Of 229 workers, 109 (48%) participated in the first survey and 87 (38%) in the second. At baseline, 77% were female, 64% were aged <40, and 81% were vendors. Overall, the seroprevalence increased between surveys (61% to 89% for anti-S IgA, 53% to 91% for anti-S IgG, and 22% to 29% for anti-N IgG), but the magnitude differed by vaccination status and antibody type. The prevalence of infections decreased from 13% to 1% and most were asymptomatic. Vendor occupation was associated with IgA and IgG anti-S in males but not females. Using a mask was a protective measure. Most market workers had been exposed to SARS-CoV-2, possibly through asymptomatic individuals. Masking is a protective measure to be prioritized during high transmission. © 2023 by the authors. |
Estimated public health impact of concurrent mask mandate and vaccinate-or-test requirement in Illinois, October to December 2021
Castonguay FM , Barnes A , Jeon S , Fornoff J , Adhikari BB , Fischer LS , Greening B Jr , Hassan AO , Kahn EB , Kang GJ , Kauerauf J , Patrick S , Vohra S , Meltzer MI . BMC Public Health 2024 24 (1) 1013 BACKGROUND: Facing a surge of COVID-19 cases in late August 2021, the U.S. state of Illinois re-enacted its COVID-19 mask mandate for the general public and issued a requirement for workers in certain professions to be vaccinated against COVID-19 or undergo weekly testing. The mask mandate required any individual, regardless of their vaccination status, to wear a well-fitting mask in an indoor setting. METHODS: We used Illinois Department of Public Health's COVID-19 confirmed case and vaccination data and investigated scenarios where masking and vaccination would have been reduced to mimic what would have happened had the mask mandate or vaccine requirement not been put in place. The study examined a range of potential reductions in masking and vaccination mimicking potential scenarios had the mask mandate or vaccine requirement not been enacted. We estimated COVID-19 cases and hospitalizations averted by changes in masking and vaccination during the period covering October 20 to December 20, 2021. RESULTS: We find that the announcement and implementation of a mask mandate are likely to correlate with a strong protective effect at reducing COVID-19 burden and the announcement of a vaccinate-or-test requirement among frontline professionals is likely to correlate with a more modest protective effect at reducing COVID-19 burden. In our most conservative scenario, we estimated that from the period of October 20 to December 20, 2021, the mask mandate likely prevented approximately 58,000 cases and 1,175 hospitalizations, while the vaccinate-or-test requirement may have prevented at most approximately 24,000 cases and 475 hospitalizations. CONCLUSION: Our results indicate that mask mandates and vaccine-or-test requirements are vital in mitigating the burden of COVID-19 during surges of the virus. |
Health care workers' comfort ratings for elastomeric half mask respirators versus N95(®) filtering facepiece respirators during the COVID-19 pandemic
Pompeii L , Rios J , Kraft CS , Kasbaum M , Benavides E , Patlovich SJ , Ostrosky-Zeichner L , Hornbeck A , McClain C , Fernando RD , Sietsema M , Lane M . Workplace Health Saf 2024 21650799241238755 BACKGROUND: Reusable elastomeric half-mask respirators (EHMR) are an alternative to address shortages of disposable respirators. While respirator discomfort has been noted as a barrier to adherence to wearing an N95 filtering facepiece respirator (FFR) among health care personnel (HCP), few have examined EHMR comfort while providing patient care, which was the purpose of this study. METHOD: Among a cohort of 183 HCP, we prospectively examined how HCP rated EHMR tolerability using the Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI) questionnaire at Study Week 2 and Week 10. At the completion of the study (Week-12), HCP compared EHMR comfort with their prior N95 FFR use. Overall R-COMFI scores and three subscales (comfort, wear experience, and function) were examined as well as individual item scores. FINDINGS: The HCP reported an improved overall R-COMFI score (lower score more favorable, 30.0 vs. 28.7/47, respectively) from Week 2 to Week 10. Many individual item scores improved or remained low over this period, except difficulty communicating with patients and coworkers. The overall R-COMFI scores for the EHMR were more favorable than for the N95 FFR (33.7 vs. 37.4, respectively), with a large proportion of workers indicating their perception that EHMR fit better, provided better protection, and they preferred to wear it in pandemic conditions compared with the N95 FFR. CONCLUSION/APPLICATION TO PRACTICE: Findings suggest that the EHMR is a feasible respiratory protection device with respect to tolerance. EHMRs can be considered as a possible alternative to the N95 FFR in the health care setting. Future work is needed in the EHMR design to improve communication. |
Using Public Feedback about the use of Elastomeric Half Mask Respirators to Inform a National Deployment Study within Health Settings
Haas EJ , Greenawald LA , Furek A , D'Alessandro MM . J Int Soc Respir Prot 12/28/2021 38 (2) 92-106 Reusable elastomeric half mask respirators (EHMRs) have been encouraged for use during conventional, contingency, and crisis capacity in healthcare delivery settings as an alternative to disposable N95 filtering facepiece respirators (FFRs). However, standard, operationalized guidelines for implementing EHMRs in healthcare and first responder settings are needed to facilitate such integration. Specifically, research is needed to identify and address specialized concerns in healthcare delivery settings beyond hospitals to understand the widespread barriers to EHMR use and how organizational culture can support or hinder EHMR adoption. The Strategic National Stockpile (SNS) requested support from the National Institute for Occupational Safety and Health (NIOSH) to develop its strategy to purchase and distribute EHMRs to interested health organizations. To support this SNS effort, NIOSH published a Federal Register Notice (FRN) to request formative input from the public on the nationwide distribution of EHMRs and provided the technical analysis of the responses. Twenty-two representatives from first responder organizations, healthcare and dental associations, manufacturers, higher education, medical/nursing societies, and a union provided comments for consideration. This feedback was qualitatively analyzed to identify themes among the comments. This paper discusses patterns that emerged in the feedback provided within the primary topics of perceived advantages and disadvantages of EHMRs and key considerations for a successful national deployment of EHMRs. This paper also discusses how the formative feedback received was critical to informing the SNS's strategy to purchase and deploy EHMRs for longitudinal demonstration projects with the goal to produce updated EHMR implementation guidelines and best practices. |
Health and education services during the COVID-19 pandemic among young children with autism spectrum disorder and other developmental disabilities
Pazol K , Tian LH , DiGuiseppi C , Durkin MS , Fallin MD , Moody EJ , Nadler C , Powell PS , Reyes N , Robinson B , Ryerson AB , Thierry JM , Tinker SC , Wiggins LD , Yeargin-Allsopp M . J Dev Behav Pediatr 2024 45 (1) e31-e38 OBJECTIVE: Understanding how the COVID-19 pandemic affected children with disabilities is essential for future public health emergencies. We compared children with autism spectrum disorder (ASD) with those with another developmental disability (DD) and from the general population (POP) regarding (1) missed or delayed appointments for regular health/dental services, immunizations, and specialty services; (2) reasons for difficulty accessing care; and (3) use of remote learning and school supports. METHOD: Caregivers of children previously enrolled in the Study to Explore Early Development, a case-control study of children with ASD implemented during 2017 to 2020, were recontacted during January-June 2021 to learn about services during March-December 2020. Children were classified as ASD, DD, or POP during the initial study and were aged 3.4 to 7.5 years when their caregivers were recontacted during the pandemic. RESULTS: Over half of all children missed or delayed regular health/dental appointments (58.4%-65.2%). More children in the ASD versus DD and POP groups missed or delayed specialty services (75.7%, 58.3%, and 22.8%, respectively) and reported difficulties obtaining care of any type because of issues using telehealth and difficulty wearing a mask. During school closures, a smaller proportion of children with ASD versus another DD were offered live online classes (84.3% vs 91.1%), while a larger proportion had disrupted individualized education programs (50.0% vs 36.2%). CONCLUSION: Minimizing service disruptions for all children and ensuring continuity of specialty care for children with ASD is essential for future public health emergencies. Children may need additional services to compensate for disruptions during the pandemic. |
A United Response to COVID-19—an Artist’s Perspective
Breedlove B , Cassell CH , Raghunathan PL . Emerg Infect Dis 2022 28 S302-3 During mid-March 2020, the World Health Organization (WHO) declared that the spread of COVID-19, the respiratory illness caused by SARS-CoV-2, was a pandemic. This novel emerging infectious disease spread insidiously and swiftly around the globe, undeterred by geographic borders. Countries reacted to COVID-19 with attempts to control transmission, including isolation and quarantine orders, social distancing recommendations, and mask requirements. Responses at the local, national, regional, and international levels involved public health experts, field epidemiologists (disease detectives), clinicians, researchers, policy makers, political leaders, and civil authorities. | | Artists from across the globe also responded to the effects of COVID-19 in myriad ways, communicating a wide range of perspectives and experiences about the pandemic through imagery, music, dance, and writing. Efforts to collect and share some of this artistic output via online platforms helped connect artists and audiences to a greater degree than would otherwise have been possible during the pandemic. For example, in spring 2020 the Washington Post invited readers to submit artwork created during the early months of the COVID-19 outbreak. The paper featured 20 works, selected from more than 650 submissions, in the article “The Best Art Created by Washington Post Readers during the Pandemic.” Michael Cavna, a writer-artist-cartoonist who penned the story, explained, “The Post considered not only the quality and creativity of the art, but also the fascinating accompanying backstories. Enduring quarantines, some artists rendered what isolation and loneliness felt like, while others depicted longed-for social scenes from a pre-pandemic time.” |
Provider experiences with daily use of elastomeric half-mask respirators in healthcare
Lane M , Pompeii L , Rios J , Benavides E , Kasbaum M , Patlovich S , Ostrosky-Zeichner L , Hornbeck A , McClain C , Fernando R , Sietsema M , Kraft C . Am J Infect Control 2024 BACKGROUND: During public health emergencies, demand for N95® filtering facepiece respirators (N95 FFRs) can outpace supply. Elastomeric half mask respirators (EHMRs) are a potential alternative that are reusable and provide the same or higher levels of protection. This study sought to examine the practical aspects of EHMR use among healthcare personnel (HCP). METHODS: Between September and December 2021, 183 HCP at two tertiary referral centers participated in this three-month EHMR deployment, wearing the EHMR whenever respiratory protection was required according to hospital protocols (i.e., when an N95 FFR would typically be worn) and responding to surveys about their experience. RESULTS: Participants wore EHMRs typically 1-3 hours per shift, reported disinfecting the respirator after 85% of removals, and reported high confidence in using the EHMR following the study. EHMRs caused minimal interference with patient care tasks, though they did inhibit communication. DISCUSSION: HCP who had not previously worn an EHMR were able to wear it as an alternative to an N95 FFR without much reported interference with their job tasks and with high disinfection compliance. CONCLUSION: This study highlights the feasibility of deployment of EHMRs during a public health emergency when an alternative respirator option is necessary. |
Identifying leadership practices to support the uptake of reusable elastomeric half mask respirators in health delivery settings
Haas EJ , Furek A , Greenawald LA . Healthc Manage Forum 2024 8404704241226698 An increase in reusable elastomeric half mask respirators among healthcare personnel has been documented during pandemic emergencies; however, research has not detailed leadership practices to support their use. Forty-three organizations implemented EHMRs received from the United States federal government which prompted interviews with 73 individuals who managed respirator distribution and fit testing between October 2021 and November 2022. Interview data was qualitatively analyzed. Themes around organizational culture and leadership practices emerged when discussing how elastomeric half mask respirators were integrated into health delivery settings including communication and outreach methods to aid worker support. Example included on-line and hands-on training, peer support, leadership support, and a culture that supports respirator use. To support a shift to reusable respiratory protection being procured and implemented, organizational- and individual-level perspectives are needed. Employee engagement, respirator champions, and updated verbal and written communication mechanisms are important takeaways for leaders to consider during any routine or emergency scenario. |
Untangling the effects of multiple exposures with a common reference group in an epidemiologic study: A practical revisit
Fontaine RE , He Y , Zhu BP . PLoS One 2023 18 (12) e0295915 When assessing multiple exposures in epidemiologic studies, epidemiologists often use multivariable regression models with main effects only to control for confounding. This method can mask the true effects of individual exposures, potentially leading to wrong conclusions. We revisited a simple, practical, and often overlooked approach to untangle effects of the exposures of interest, in which the combinations of all levels of the exposures of interest are recoded into a single, multicategory variable. One category, usually the absence of all exposures of interest, is selected as the common reference group (CRG). All other categories representing individual and joint exposures are then compared to the CRG using indicator variables in a regression model or in a 2×2 contingency table analysis. Using real data examples, we showed that using the CRG analysis results in estimates of individual and joint effects that are mutually comparable and free of each other's confounding effects, yielding a clear, accurate, intuitive, and simple summarization of epidemiologic study findings involving multiple exposures of interest. |
US county-level variation in preterm birth rates, 2007-2019
Khan SS , Vaughan AS , Harrington K , Seegmiller L , Huang X , Pool LR , Davis MM , Allen NB , Capewell S , O'Flaherty M , Miller GE , Mehran R , Vogel B , Kershaw KN , Lloyd-Jones DM , Grobman WA . JAMA Netw Open 2023 6 (12) e2346864 ![]() IMPORTANCE: Preterm birth is a leading cause of preventable neonatal morbidity and mortality. Preterm birth rates at the national level may mask important geographic variation in rates and trends at the county level. OBJECTIVE: To estimate age-standardized preterm birth rates by US county from 2007 to 2019. DESIGN, SETTING, AND PARTICIPANTS: This serial cross-sectional study used data from the National Center for Health Statistics composed of all live births in the US between 2007 and 2019. Data analyses were performed between March 22, 2022, and September 29, 2022. MAIN OUTCOMES AND MEASURES: Age-standardized preterm birth (<37 weeks' gestation) and secondarily early preterm birth (<34 weeks' gestation) rates by county and year calculated with a validated small area estimation model (hierarchical bayesian spatiotemporal model) and percent change in preterm birth rates using log-linear regression models. RESULTS: Between 2007 and 2019, there were 51 044 482 live births in 2383 counties. In 2007, the national age-standardized preterm birth rate was 12.6 (95% CI, 12.6-12.7) per 100 live births. Preterm birth rates varied significantly among counties, with an absolute difference between the 90th and 10th percentile counties of 6.4 (95% CI, 6.2-6.7). The gap between the highest and lowest counties for preterm births was 20.7 per 100 live births in 2007. Several counties in the Southeast consistently had the highest preterm birth rates compared with counties in California and New England, which had the lowest preterm birth rates. Although there was no statistically significant change in preterm birth rates between 2007 and 2019 at the national level (percent change, -5.0%; 95% CI, -10.7% to 0.9%), increases occurred in 15.4% (95% CI, 14.1%-16.9%) of counties. The absolute and relative geographic inequalities were similar across all maternal age groups. Higher quartile of the Social Vulnerability Index was associated with higher preterm birth rates (quartile 4 vs quartile 1 risk ratio, 1.34; 95% CI, 1.31-1.36), which persisted across the study period. Similar patterns were observed for early preterm birth rates. CONCLUSIONS AND RELEVANCE: In this serial cross-sectional study of county-level preterm and early preterm birth rates, substantial geographic disparities were observed, which were associated with place-based social disadvantage. Stability in aggregated rates of preterm birth at the national level masked increases in nearly 1 in 6 counties between 2007 and 2019. |
Knowledge of COVID-19 symptoms, transmission, and prevention: Evidence from health and demographic surveillance in Southern Mozambique
Nhacolo A , Madewell ZJ , Muir JA , Sacoor C , Xerinda E , Matsena T , Jamisse E , Bassat Q , Whitney CG , Mandomando I , Cunningham SA . PLOS Glob Public Health 2023 3 (11) e0002532 Understanding community members' knowledge of SARS-CoV-2 transmission and prevention is essential for directing public health interventions to reduce disease spread and improve vaccination coverage. Here, we describe knowledge of COVID-19 transmission, prevention, and symptoms among community residents in Mozambique. We conducted a cross-sectional survey among 33,087 households in a Health and Demographic Surveillance System in Manhiça, Mozambique. Participants were recruited in April 2021 before the Delta variant wave to the peak of Omicron cases in February 2022. Principal components analysis was used to create scores representing knowledge of COVID-19 symptoms, transmission, and prevention. Multiple imputation and quasi-Poisson regression were used to examine associations between demographic characteristics and sources of COVID-19 information, and knowledge of COVID-19 symptoms, transmission, and prevention. We examined whether sources of COVID-19 information mediated the relationship between educational attainment and knowledge of symptoms, transmission, and prevention. Across this rural community, 98.2%, 97.0%, and 85.1% of respondents reported knowing how COVID-19 could be prevented, that SARS-CoV-2 can cause disease, and how SARS-CoV-2 is transmitted, respectively. The most recognized COVID-19 symptoms were cough (51.2%), headaches (44.9%), and fever (44.5%); transmission mechanisms were saliva droplets (50.5%) or aerosol (46.9%) from an infected person; and prevention measures were handwashing (91.9%) and mask-wearing (91.8%). Characteristics associated with greater knowledge of symptoms, transmission, and prevention included having at least primary education, older age, employment, higher wealth, and Christian religion. Respondents who had experienced COVID-19 symptoms were also more likely to possess knowledge of symptoms, transmission, and prevention. Receiving information from television, WhatsApp, radio, and hospital, mediated the relationship between educational attainment and knowledge scores. These findings support the need for outreach and for community-engaged messaging to promote prevention measures, particularly among people with low education. |
Barriers to COVID-19 prevention measures among people experiencing homelessness with substance use disorder or serious mental illness
Meehan AA , Jeffers A , Barker J , Ray CM , Laws RL , Fields VL , Miedema SS , Cha S , Cassell CH , DiPietro B , Cary M , Yang M , McLendon H , Marcus R , Mosites E . J Prev (2022) 2023 44 (6) 663-678 People experiencing homelessness (PEH) are at disproportionate risk of becoming infected and having severe illness from coronavirus disease 2019 (COVID-19), especially when residing in congregate settings like homeless shelters. Behavioral health problems related to substance use disorder (SUD) and severe mental illness (SMI) may have created additional challenges for PEH to practice prevention measures like mask wearing, physical distancing, handwashing, and quarantine and isolation. The study objective was to understand the perceived barriers PEH face regarding COVID-19 non-pharmaceutical prevention strategies and identify recommendations for overcoming barriers. From August-October 2020, qualitative phone interviews with 50 purposively selected behavioral health professionals across the United States serving PEH with SUD or SMI were conducted. Professionals described that PEH faced barriers to prevention that were structural (e.g., access to necessary resources), behavioral (related to SUD or SMI), or related to the priority of other needs. Recommendations to overcome these barriers included providing free prevention resources (e.g., masks and hand sanitizer), providing education about importance of prevention strategies, and prioritizing access to stable housing. Interviews took place before COVID-19 vaccines were available, so barriers to vaccination are not included in this paper. Findings can help support tailored approaches during COVID-19 and future public health threats. |
Elastomeric half-mask respirator disinfection practices among healthcare personnel
Hines SE , Thurman P , Zhuang E , Chen H , McDiarmid M , Chalikonda S , Angelilli S , Waltenbaugh H , Napoli M , Haas E , McClain C , Sietsema M , Fernando R . Am J Ind Med 2023 66 (12) 1056-1068 BACKGROUND: Disposable N95 respirator shortages during the COVID-19 and 2009 H1N1 influenza pandemics highlighted the need for reusable alternatives, such as elastomeric half-mask respirators (EHMRs). Two US medical organizations deployed reusable EHMRs during the COVID-19 response. In addition to wipe-based disinfection following patient care episodes expected per local policies at both organizations, postshift centralized cleaning and disinfection (C&D) was expected at one site (A), permitting shared-pool EHMR use, and optional at the other (Site B), where EHMRs were issued to individuals. Using a survey, we evaluated disinfection practices reported by EHMR users and predictors of disinfection behaviors and perceptions. METHODS: Surveys assessed EHMR disinfection practices, occupational characteristics, EHMR use frequency, training, and individual-issue versus shared-pool EHMR use. RESULTS: Of 1080 EHMR users completing the survey, 76% reported that they disinfect the EHMR after each patient encounter, which was the expected practice at both sites. Increasing EHMR use, recall of disinfection training, and work in intensive care or emergency settings significantly influenced higher reporting of this practice. 36% of respondents reported using centralized C&D, although reporting was higher at the site (A) where this was expected (53%). Confidence in cleanliness of the EHMR following centralized C&D was not influenced by individual versus shared-pool EHMR issue. CONCLUSIONS: Most EHMR users reported adherence with expected post-care individual-based disinfection of EHMRs but did not necessarily use standardized, centralized C&D. Future efforts to limit reliance on behavior related to respirator disinfection may improve EHMR implementation in healthcare to avert dependence on single-use, disposable N95 respirators. |
Examining the roles of training, fit testing, and safety climate on user confidence in respiratory protection: A case example with reusable respirators in health delivery settings
Edirisooriya M , Haas EJ . Sustainability 2023 15 (17) A lack of confidence in the efficacy of respiratory protection can contribute to uncertainty among workers and cast doubt on workplace safety. To date, no research has been conducted to study and understand the introduction of elastomeric half-mask respirators (EHMRs)—without exhalation valves (EVs) or with exhalation valve filters (EVFs), both representing new designs that address source control—in the workplace. To study this issue, researchers collaborated with partners at 32 health delivery settings that received EHMRs from the Strategic National Stockpile during the COVID-19 pandemic. EHMR users (n = 882) completed an online survey between October 2021 and September 2022. Analyses demonstrated that employees were statistically significantly more confident in the efficacy of EHMRs with no EV/with an EVF (including the efficacy in protecting the user from COVID-19) if they had been fit tested and received training. Respondents were also statistically significantly more confident in the efficacy of their EHMR if they had a more positive perception of their organization’s safety climate. The results provide insights for tailored fit testing and training procedures as manufacturers continue to improve respirator models to enhance worker comfort and use. Results also show that, even during a public health emergency, the role of safety climate cannot be ignored as an organizational factor to support worker knowledge, attitudes, and participation in health and safety behaviors specific to respirator use. © 2023 by the authors. |
Total outward leakage of half-mask respirators and surgical masks used for source control
Myers WR , Yang W , Ryan KJ , Bergman M , Fisher E , Soo JC , Zhuang Z . J Occup Environ Hyg 2023 1-15 Both respirators and surgical masks (SM) are used as source control devices. During the COVID-19 pandemic, there was much interest in understanding the extent of particle total outward leakage (TOL) from these devices. The objective of this study was to quantify the TOL for five categories of devices: SMs, National Institute for Occupational Safety and Health (NIOSH®) Approved N95(®) filtering facepiece respirators (FFRs) without exhalation valves, NIOSH Approved N95 FFRs with exhalation valves (N95 FFRV), NIOSH Approved elastomeric half-mask respirators (EHMRs) with exhalation valves, and NIOSH Approved EHMRs with an SM covering the exhalation valve (EHMRSM). A benchtop test system was designed to test two models of each device category. Each device was mounted on a headform at three faceseal levels (0% faceseal, 50% faceseal, and 100% faceseal). At each faceseal level, the TOL was assessed at three flowrates of minute ventilations of 17, 28, and 39 L/min. The experimental design was a split-split-plot configuration. Device type, faceseal level, flowrate, and the interaction of device type and faceseal level were found to have a significant effect ( P - Value <0.05) on the TOL.This study found that the N95 FFRs without exhalation valves had the lowest mean TOL. The SMs had about three times higher TOL than the N95 FFRs without exhalation valves. The TOL of the N95 FFRV was comparable to that of the SM at 0% and 50% faceseal on average over all conditions, but the N95 FFRV had a significantly higher TOL than the SM at a 100% faceseal. The EHMRs had the highest TOL because of the exhalation valve. Using an SM to cover the exhalation valve did not improve the EHMRs' efficiency in mitigating the TOL. Caution should be exercised when using N95 FFRVs as a source control measure against respiratory activities with heavy work rates, such as performing CPR. Results of this study showed that reduced faceseal leakage for N95 FFRs and SMs improves source control. |
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