Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-30 (of 54 Records) |
Query Trace: Swerdlow DL[original query] |
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Estimated preventable COVID-19-associated deaths due to non-vaccination in the United States
Jia KM , Hanage WP , Lipsitch M , Johnson AG , Amin AB , Ali AR , Scobie HM , Swerdlow DL . Eur J Epidemiol 2023 1-4 While some studies have previously estimated lives saved by COVID-19 vaccination, we estimate how many deaths could have been averted by vaccination in the US but were not because of a failure to vaccinate. We used a simple method based on a nationally representative dataset to estimate the preventable deaths among unvaccinated individuals in the US from May 30, 2021 to September 3, 2022 adjusted for the effects of age and time. We estimated that at least 232,000 deaths could have been prevented among unvaccinated adults during the 15 months had they been vaccinated with at least a primary series. While uncertainties exist regarding the exact number of preventable deaths and more granular data are needed on other factors causing differences in death rates between the vaccinated and unvaccinated groups to inform these estimates, this method is a rapid assessment on vaccine-preventable deaths due to SARS-CoV-2 that has crucial public health implications. The same rapid method can be used for future public health emergencies. |
Modeling the potential impact of administering vaccines against Clostridioides difficile infection to individuals in healthcare facilities.
Toth DJA , Keegan LT , Samore MH , Khader K , O'Hagan JJ , Yu H , Quintana A , Swerdlow DL . Vaccine 2020 38 (37) 5927-5932 BACKGROUND: A vaccine against Clostridioides difficile infection (CDI) is in development. While the vaccine has potential to both directly protect those vaccinated and mitigate transmission by reducing environmental contamination, the impact of the vaccine on C. difficile colonization remains unclear. Consequently, the transmission-reduction effect of the vaccine depends on the contribution of symptomatic CDI to overall transmission of C. difficile. METHODS: We designed a simulation model of CDI among patients in a network of 10 hospitals and nursing homes and calibrated the model using estimates of transmissibility from whole genome sequencing studies that estimated the fraction of CDI attributable to transmission from other CDI patients. We assumed the vaccine reduced the rate of progression to CDI among carriers by 25-95% after completion of a 3-dose vaccine course administered to randomly chosen patients at facility discharge. We simulated the administration of this vaccination campaign and tallied effects over 5 years. RESULTS: We estimated 30 times higher infectivity of CDI patients compared to other carriers. Simulations of the vaccination campaign produced an average reduction of 3-16 CDI cases per 1000 vaccinated patients, with 2-11 of those cases prevented among those vaccinated and 1-5 prevented among unvaccinated patients. CONCLUSIONS: Our findings demonstrate potential for a vaccine against CDI to reduce transmissions in healthcare facilities, even with no direct effect on carriage susceptibility. The vaccine's population impact will increase if received by individuals at risk for CDI onset in high-transmission settings. |
Forecasting the 2014 West African Ebola outbreak
Carias C , O'Hagan JJ , Gambhir M , Kahn EB , Swerdlow DL , Meltzer MI . Epidemiol Rev 2019 41 (1) 34-50 In 2014/15 an Ebola outbreak of unprecedented dimensions afflicted the West African countries of Liberia, Guinea, and Sierra Leone. We performed a systematic review of manuscripts that forecasted the outbreak while it was occurring, and derive implications on the ways results could be interpreted by policy-makers. We reviewed 26 manuscripts, published between 2014 and April 2015, that presented forecasts of the West African Ebola outbreak. Forecasted case counts varied widely. An important determinant of forecast accuracy for case counts was how far into the future predictions were made. Generally, those that made forecasts less than 2 months into the future tended to be more accurate than those that made forecasts more than 10 weeks into the future. The exceptions were parsimonious statistical models in which the decay of the rate of spread of the pathogen among susceptible individuals was dealt with explicitly. Regarding future outbreaks, the most important lessons for policy makers when using similar modeling results are: i) uncertainty of forecasts will be higher in the beginning of the outbreak, ii) when data are limited, forecasts produced by models designed to inform specific decisions should be used in complimentary fashion for robust decision making - for this outbreak, two statistical models produced the most reliable case counts forecasts, but did not allow to understand the impact of interventions, while several compartmental models could estimate the impact of interventions but required data that was not available; iii) timely collection of essential data is necessary for optimal model use. |
Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies
Miernyk KM , Bulkow LR , Gold BD , Bruce MG , Hurlburt DH , Griffin PM , Swerdlow DL , Cook K , Hennessy TW , Parkinson AJ . Helicobacter 2018 23 (3) e12482 BACKGROUND: Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection. METHODS: A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old. RESULTS: We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age >/= 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered. CONCLUSIONS: Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity. |
Middle East Respiratory Syndrome (MERS)
Rasmussen SA , Watson AK , Swerdlow DL . Microbiol Spectr 2016 4 (3) Since the identification of the first patients with Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012, over 1,600 cases have been reported as of February 2016. Most cases have occurred in Saudi Arabia or in other countries on or near the Arabian Peninsula, but travel-associated cases have also been seen in countries outside the Arabian Peninsula. MERS-CoV causes a severe respiratory illness in many patients, with a case fatality rate as high as 40%, although when contacts are investigated, a significant proportion of patients are asymptomatic or only have mild symptoms. At this time, no vaccines or treatments are available. Epidemiological and other data suggest that the source of most primary cases is exposure to camels. Person-to-person transmission occurs in household and health care settings, although sustained and efficient person-to-person transmission has not been observed. Strict adherence to infection control recommendations has been associated with control of previous outbreaks. Vigilance is needed because genomic changes in MERS-CoV could result in increased transmissibility, similar to what was seen in severe acute respiratory syndrome coronavirus (SARS-CoV). |
Risk factors for Middle East respiratory syndrome coronavirus infection among healthcare personnel
Alraddadi BM , Al-Salmi HS , Jacobs-Slifka K , Slayton RB , Estivariz CF , Geller AI , Al-Turkistani HH , Al-Rehily SS , Alserehi HA , Wali GY , Alshukairi AN , Azhar EI , Haynes L , Swerdlow DL , Jernigan JA , Madani TA . Emerg Infect Dis 2016 22 (11) 1915-1920 Healthcare settings can amplify transmission of Middle East respiratory syndrome coronavirus (MERS-CoV), but knowledge gaps about the epidemiology of transmission remain. We conducted a retrospective cohort study among healthcare personnel in hospital units that treated MERS-CoV patients. Participants were interviewed about exposures to MERS-CoV patients, use of personal protective equipment, and signs and symptoms of illness after exposure. Infection status was determined by the presence of antibodies against MERS-CoV. To assess risk factors, we compared infected and uninfected participants. Healthcare personnel caring for MERS-CoV patients were at high risk for infection, but infection most often resulted in a relatively mild illness that might be unrecognized. In the healthcare personnel cohort reported here, infections occurred exclusively among those who had close contact with MERS-CoV patients. |
Estimation of severe Middle East Respiratory Syndrome cases in the Middle East, 2012-2016
O'Hagan JJ , Carias C , Rudd JM , Pham HT , Haber Y , Pesik N , Cetron MS , Gambhir M , Gerber SI , Swerdlow DL . Emerg Infect Dis 2016 22 (10) 1797-9 Using data from travelers to 4 countries in the Middle East, we estimated 3,250 (95% CI 1,300-6,600) severe cases of Middle East respiratory syndrome occurred in this region during September 2012-January 2016. This number is 2.3-fold higher than the number of laboratory-confirmed cases recorded in these countries. |
Outbreak of Middle East Respiratory Syndrome at Tertiary Care Hospital, Jeddah, Saudi Arabia, 2014
Hastings DL , Tokars JI , Abdel Aziz IZ , Alkhaldi KZ , Bensadek AT , Alraddadi BM , Jokhdar H , Jernigan JA , Garout MA , Tomczyk SM , Oboho IK , Geller AI , Arinaminpathy N , Swerdlow DL , Madani TA . Emerg Infect Dis 2016 22 (5) 794-801 During March-May 2014, a Middle East respiratory syndrome (MERS) outbreak occurred in Jeddah, Saudi Arabia, that included many persons who worked or received medical treatment at King Fahd General Hospital. We investigated 78 persons who had laboratory-confirmed MERS during March 2-May 10 and documented contact at this hospital. The 78 persons with MERS comprised 53 patients, 16 healthcare workers, and 9 visitors. Among the 53 patients, the most probable sites of acquisition were the emergency department (22 patients), inpatient areas (17), dialysis unit (11), and outpatient areas (3). Infection control deficiencies included limited separation of suspected MERS patients, patient crowding, and inconsistent use of infection control precautions; aggressive improvements in these deficiencies preceded a decline in cases. MERS coronavirus transmission probably was multifocal, occurring in multiple hospital settings. Continued vigilance and strict application of infection control precautions are necessary to prevent future MERS outbreaks. |
Exportations of symptomatic cases of MERS-CoV infection to countries outside the Middle East
Carias C , O'Hagan JJ , Jewett A , Gambhir M , Cohen NJ , Haber Y , Pesik N , Swerdlow DL . Emerg Infect Dis 2016 22 (3) 723-5 In 2012, an outbreak of infection with Middle East respiratory syndrome coronavirus (MERS-CoV), was detected in the Arabian Peninsula. Modeling can produce estimates of the expected annual number of symptomatic cases of MERS-CoV infection exported and the likelihood of exportation from source countries in the Middle East to countries outside the region. |
Enhancing disease surveillance with novel data streams: challenges and opportunities
Althouse BM , Scarpino SV , Meyers LA , Ayers JW , Bargsten M , Baumbach J , Brownstein JS , Castro L , Clapham H , Cummings DAT , Del Valle S , Eubank S , Fairchild G , Finelli L , Generous N , George D , Harper DR , Hébert-Dufresne L , Johansson MA , Konty K , Lipsitch M , Milinovich G , Miller JD , Nsoesie EO , Olson DR , Paul M , Polgreen PM , Priedhorsky R , Read JM , Rodríguez-Barraquer I , Smith DJ , Stefansen C , Swerdlow DL , Thompson D , Vespignani A , Wesolowski A . EPJ Data Sci 2015 4 (1) 17 Novel data streams (NDS), such as web search data or social media updates, hold promise for enhancing the capabilities of public health surveillance. In this paper, we outline a conceptual framework for integrating NDS into current public health surveillance. Our approach focuses on two key questions: What are the opportunities for using NDS and what are the minimal tests of validity and utility that must be applied when using NDS? Identifying these opportunities will necessitate the involvement of public health authorities and an appreciation of the diversity of objectives and scales across agencies at different levels (local, state, national, international). We present the case that clearly articulating surveillance objectives and systematically evaluating NDS and comparing the performance of NDS to existing surveillance data and alternative NDS data is critical and has not sufficiently been addressed in many applications of NDS currently in the literature. |
Clinicopathologic, immunohistochemical, and ultrastructural findings of a fatal case of Middle East respiratory syndrome coronavirus infection in United Arab Emirates, April 2014
Ng DL , Al Hosani F , Keating MK , Gerber SI , Jones TL , Metcalfe MG , Tong S , Tao Y , Alami NN , Haynes LM , Mutei MA , Abdel-Wareth L , Uyeki TM , Swerdlow DL , Barakat M , Zaki SR . Am J Pathol 2016 186 (3) 652-8 Middle East respiratory syndrome coronavirus (MERS-CoV) infection causes an acute respiratory illness and is associated with a high case fatality rate; however, the pathogenesis of severe and fatal MERS-CoV infection is unknown. We describe the histopathologic, immunohistochemical, and ultrastructural findings from the first autopsy performed on a fatal case of MERS-CoV in the world, which was related to a hospital outbreak in the United Arab Emirates in April 2014. The main histopathologic finding in the lungs was diffuse alveolar damage. Evidence of chronic disease, including severe peripheral vascular disease, patchy cardiac fibrosis, and hepatic steatosis, was noted in the other organs. Double staining immunoassays that used anti-MERS-CoV antibodies paired with immunohistochemistry for cytokeratin and surfactant identified pneumocytes and epithelial syncytial cells as important targets of MERS-CoV antigen; double immunostaining with dipeptidyl peptidase 4 showed colocalization in scattered pneumocytes and syncytial cells. No evidence of extrapulmonary MERS-CoV antigens were detected, including the kidney. These results provide critical insights into the pathogenesis of MERS-CoV in humans. |
Risk factors for primary Middle East respiratory syndrome coronavirus illness in humans, Saudi Arabia, 2014
Alraddadi BM , Watson JT , Almarashi A , Abedi GR , Turkistani A , Sadran M , Housa A , Almazroa MA , Alraihan N , Banjar A , Albalawi E , Alhindi H , Choudhry AJ , Meiman JG , Paczkowski M , Curns A , Mounts A , Feikin DR , Marano N , Swerdlow DL , Gerber SI , Hajjeh R , Madani TA . Emerg Infect Dis 2016 22 (1) 49-55 Risk factors for primary Middle East respiratory syndrome coronavirus (MERS-CoV) illness in humans are incompletely understood. We identified all primary MERS-CoV cases reported in Saudi Arabia during March-November 2014 by excluding those with history of exposure to other cases of MERS-CoV or acute respiratory illness of unknown cause or exposure to healthcare settings within 14 days before illness onset. Using a case-control design, we assessed differences in underlying medical conditions and environmental exposures among primary case-patients and 2-4 controls matched by age, sex, and neighborhood. Using multivariable analysis, we found that direct exposure to dromedary camels during the 2 weeks before illness onset, as well as diabetes mellitus, heart disease, and smoking, were each independently associated with MERS-CoV illness. Further investigation is needed to better understand animal-to-human transmission of MERS-CoV. |
Salmonella enterica infections in the United States and assessment of coefficients of variation: a novel approach to identify epidemiologic characteristics of individual serotypes, 1996-2011
Boore AL , Hoekstra RM , Iwamoto M , Fields PI , Bishop RD , Swerdlow DL . PLoS One 2015 10 (12) e0145416 BACKGROUND: Despite control efforts, salmonellosis continues to cause an estimated 1.2 million infections in the United States (US) annually. We describe the incidence of salmonellosis in the US and introduce a novel approach to examine the epidemiologic similarities and differences of individual serotypes. METHODS: Cases of salmonellosis in humans reported to the laboratory-based National Salmonella Surveillance System during 1996-2011 from US states were included. Coefficients of variation were used to describe distribution of incidence rates of common Salmonella serotypes by geographic region, age group and sex of patient, and month of sample isolation. RESULTS: During 1996-2011, more than 600,000 Salmonella isolates from humans were reported, with an average annual incidence of 13.1 cases/100,000 persons. The annual reported rate of Salmonella infections did not decrease during the study period. The top five most commonly reported serotypes, Typhimurium, Enteritidis, Newport, Heidelberg, and Javiana, accounted for 62% of fully serotyped isolates. Coefficients of variation showed the most geographically concentrated serotypes were often clustered in Gulf Coast states and were also more frequently found to be increasing in incidence. Serotypes clustered in particular months, age groups, and sex were also identified and described. CONCLUSIONS: Although overall incidence rates of Salmonella did not change over time, trends and epidemiological factors differed remarkably by serotype. A better understanding of Salmonella, facilitated by this comprehensive description of overall trends and unique characteristics of individual serotypes, will assist in responding to this disease and in planning and implementing prevention activities. |
Net costs due to seasonal influenza vaccination - United States, 2005-2009
Carias C , Reed C , Kim IK , Foppa IM , Biggerstaff M , Meltzer MI , Finelli L , Swerdlow DL . PLoS One 2015 10 (7) e0132922 BACKGROUND: Seasonal influenza causes considerable morbidity and mortality across all age groups, and influenza vaccination was recommended in 2010 for all persons aged 6 months and above. We estimated the averted costs due to influenza vaccination, taking into account the seasonal economic burden of the disease. METHODS: We used recently published values for averted outcomes due to influenza vaccination for influenza seasons 2005-06, 2006-07, 2007-08, and 2008-09, and age cohorts 6 months-4 years, 5-19 years, 20-64 years, and 65 years and above. Costs were calculated according to a payer and societal perspective (in 2009 US$), and took into account medical costs and productivity losses. RESULTS: When taking into account direct medical costs (payer perspective), influenza vaccination was cost saving only for the older age group (65≥) in seasons 2005-06 and 2007-08. Using the same perspective, influenza vaccination resulted in total costs of $US 1.7 billion (95%CI: $US 0.3-4.0 billion) in 2006-07 and $US 1.8 billion (95%CI: $US 0.1-4.1 billion) in 2008-09. When taking into account a societal perspective (and including the averted lost earnings due to premature death) averted deaths in the older age group influenced the results, resulting in cost savings for all ages combined in season 07-08. DISCUSSION: Influenza vaccination was cost saving in the older age group (65≥) when taking into account productivity losses and, in some seasons, when taking into account medical costs only. Averted costs vary significantly per season; however, in seasons where the averted burden of deaths is high in the older age group, averted productivity losses due to premature death tilt overall seasonal results towards savings. Indirect vaccination effects and the possibility of diminished case severity due to influenza vaccination were not considered, thus the averted burden due to influenza vaccine may be even greater than reported. |
CDC’s early response to a novel viral disease, Middle East respiratory syndrome coronavirus (MERS-CoV), September 2012-May 2014
Williams HA , Dunville RL , Gerber SI , Erdman DD , Pesik N , Kuhar D , Mason KA , Haynes L , Rotz L , Pierre JS , Poser S , Bunga S , Pallansch MA , Swerdlow DL . Public Health Rep 2015 130 (4) 307-317 The first ever case of Middle East Respiratory Syndrome Coronavirus (MERSCoV) was reported in September 2012. This report describes the approaches taken by CDC, in collaboration with the World Health Organization (WHO) and other partners, to respond to this novel virus, and outlines the agency responses prior to the first case appearing in the United States in May 2014. During this time, CDC’s response integrated multiple disciplines and was divided into three distinct phases: before, during, and after the initial activation of its Emergency Operations Center. CDC’s response to MERS-CoV required a large effort, deploying at least 353 staff members who worked in the areas of surveillance, laboratory capacity, infection control guidance, and travelers’ health. This response built on CDC’s experience with previous outbreaks of other pathogens and provided useful lessons for future emerging threats. |
Lack of transmission among close contacts of patient with case of Middle East Respiratory Syndrome imported into the United States, 2014
Breakwell L , Pringle K , Chea N , Allen D , Allen S , Richards S , Pantones P , Sandoval M , Liu L , Vernon M , Conover C , Chugh R , DeMaria A , Burns R , Smole S , Gerber SI , Cohen NJ , Kuhar D , Haynes LM , Schneider E , Kumar A , Kapoor M , Madrigal M , Swerdlow DL , Feikin DR . Emerg Infect Dis 2015 21 (7) 1128-34 In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. Of 61 identified contacts, 56 were interviewed. HCP exposures occurred most frequently in the emergency department (69%) and among nurses (47%); some HCP had contact with respiratory secretions. Household and community contacts had brief contact (e.g., hugging). All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate. |
A change in vaccine efficacy and duration of protection explains recent rises in pertussis incidence in the United States
Gambhir M , Clark TA , Cauchemez S , Tartof SY , Swerdlow DL , Ferguson NM . PLoS Comput Biol 2015 11 (4) e1004138 Over the past ten years the incidence of pertussis in the United States (U.S.) has risen steadily, with 2012 seeing the highest case number since 1955. There has also been a shift over the same time period in the age group reporting the largest number of cases (aside from infants), from adolescents to 7-11 year olds. We use epidemiological modelling and a large case incidence dataset to explain the upsurge. We investigate several hypotheses for the upsurge in pertussis cases by fitting a suite of dynamic epidemiological models to incidence data from the National Notifiable Disease Surveillance System (NNDSS) between 1990-2009, as well as incidence data from a variety of sources from 1950-1989. We find that: the best-fitting model is one in which vaccine efficacy and duration of protection of the acellular pertussis (aP) vaccine is lower than that of the whole-cell (wP) vaccine, (efficacy of the first three doses 80% [95% CI: 78%, 82%] versus 90% [95% CI: 87%, 94%]), increasing the rate at which disease is reported to NNDSS is not sufficient to explain the upsurge and 3) 2010-2012 disease incidence is predicted well. In this study, we use all available U.S. surveillance data to: 1) fit a set of mathematical models and determine which best explains these data and 2) determine the epidemiological and vaccine-related parameter values of this model. We find evidence of a difference in efficacy and duration of protection between the two vaccine types, wP and aP (aP efficacy and duration lower than wP). Future refinement of the model presented here will allow for an exploration of alternative vaccination strategies such as different age-spacings, further booster doses, and cocooning. |
Potential demand for respirators and surgical masks during a hypothetical influenza pandemic in the United States
Carias C , Rainisch G , Shankar M , Adhikari BB , Swerdlow DL , Bower WA , Pillai SK , Meltzer MI , Koonin LM . Clin Infect Dis 2015 60 Suppl 1 S42-51 BACKGROUND: To inform planning for an influenza pandemic, we estimated US demand for N95 filtering facepiece respirators (respirators) by healthcare and emergency services personnel and need for surgical masks by pandemic patients seeking care. METHODS: We used a spreadsheet-based model to estimate demand for 3 scenarios of respirator use: base case (usage approximately follows epidemic curve), intermediate demand (usage rises to epidemic peak and then remains constant), and maximum demand (all healthcare workers use respirators from pandemic onset). We assumed that in the base case scenario, up to 16 respirators would be required per day per intensive care unit patient and 8 per day per general ward patient. Outpatient healthcare workers and emergency services personnel would require 4 respirators per day. Patients would require 1.2 surgical masks per day. RESULTS AND CONCLUSIONS: Assuming that 20% to 30% of the population would become ill, 1.7 to 3.5 billion respirators would be needed in the base case scenario, 2.6 to 4.3 billion in the intermediate demand scenario, and up to 7.3 billion in the maximum demand scenario (for all scenarios, between 0.1 and 0.4 billion surgical masks would be required for patients). For pandemics with a lower attack rate and fewer cases (eg, 2009-like pandemic), the number of respirators needed would be higher because the pandemic would have longer duration. Providing these numbers of respirators and surgical masks represents a logistic challenge for US public health agencies. Public health officials must urgently consider alternative use strategies for respirators and surgical masks during a pandemic that may vary from current practices. |
Estimating the potential effects of a vaccine program against an emerging influenza pandemic - United States
Biggerstaff M , Reed C , Swerdlow DL , Gambhir M , Graitcer S , Finelli L , Borse RH , Rasmussen SA , Meltzer MI , Bridges CB . Clin Infect Dis 2015 60 Suppl 1 S20-9 BACKGROUND: Human illness from influenza A(H7N9) was identified in March 2013, and candidate vaccine viruses were soon developed. To understand factors that may impact influenza vaccination programs, we developed a model to evaluate hospitalizations and deaths averted considering various scenarios. METHODS: We utilized a model incorporating epidemic curves with clinical attack rates of 20% or 30% in a single wave of illness, case hospitalization ratios of 0.5% or 4.2%, and case fatality ratios of 0.08% or 0.53%. We considered scenarios that achieved 80% vaccination coverage, various starts of vaccination programs (16 or 8 weeks before, the same week of, or 8 or 16 weeks after start of pandemic), an administration rate of 10 or 30 million doses per week (the latter rate is an untested assumption), and 2 levels of vaccine effectiveness (2 doses of vaccine required; either 62% or 80% effective for persons aged <60 years, and either 43% or 60% effective for persons aged ≥60 years). RESULTS: The start date of vaccination campaigns most influenced impact; 141 000-2 200 000 hospitalizations and 11 000-281 000 deaths were averted when campaigns started before a pandemic, and <100-1 300 000 hospitalizations and 0-165 000 deaths were averted for programs beginning the same time as or after the introduction of the pandemic virus. The rate of vaccine administration and vaccine effectiveness did not influence campaign impact as much as timing of the start of campaign. CONCLUSIONS: Our findings suggest that efforts to improve the timeliness of vaccine production will provide the greatest impacts for future pandemic vaccination programs. |
Estimating the United States demand for influenza antivirals and the effect on severe influenza disease during a potential pandemic
O'Hagan JJ , Wong KK , Campbell AP , Patel A , Swerdlow DL , Fry AM , Koonin LM , Meltzer MI . Clin Infect Dis 2015 60 Suppl 1 S30-41 Following the detection of a novel influenza strain A(H7N9), we modeled the use of antiviral treatment in the United States to mitigate severe disease across a range of hypothetical pandemic scenarios. Our outcomes were total demand for antiviral (neuraminidase inhibitor) treatment and the number of hospitalizations and deaths averted. The model included estimates of attack rate, healthcare-seeking behavior, prescription rates, adherence, disease severity, and the potential effect of antivirals on the risks of hospitalization and death. Based on these inputs, the total antiviral regimens estimated to be available in the United States (as of April 2013) were sufficient to meet treatment needs for the scenarios considered. However, distribution logistics were not examined and should be addressed in future work. Treatment was estimated to avert many severe outcomes (5200-248 000 deaths; 4800-504 000 hospitalizations); however, large numbers remained (25 000-425 000 deaths; 580 000-3 700 000 hospitalizations), suggesting that the impact of combinations of interventions should be examined. |
Infectious disease modeling methods as tools for informing response to novel influenza viruses of unknown pandemic potential
Gambhir M , Bozio C , O'Hagan JJ , Uzicanin A , Johnson LE , Biggerstaff M , Swerdlow DL . Clin Infect Dis 2015 60 Suppl 1 S11-9 The rising importance of infectious disease modeling makes this an appropriate time for a guide for public health practitioners tasked with preparing for, and responding to, an influenza pandemic. We list several questions that public health practitioners commonly ask about pandemic influenza and match these with analytical methods, giving details on when during a pandemic the methods can be used, how long it might take to implement them, and what data are required. Although software to perform these tasks is available, care needs to be taken to understand: (1) the type of data needed, (2) the implementation of the methods, and (3) the interpretation of results in terms of model uncertainty and sensitivity. Public health leaders can use this article to evaluate the modeling literature, determine which methods can provide appropriate evidence for decision-making, and to help them request modeling work from in-house teams or academic groups. |
Standardizing scenarios to assess the need to respond to an influenza pandemic
Meltzer MI , Gambhir M , Atkins CY , Swerdlow DL . Clin Infect Dis 2015 60 Suppl 1 S1-8 An outbreak of human infections with an avian influenza A(H7N9) virus was first reported in eastern China by the World Health Organization on 1 April 2013 [1]. This novel influenza virus was fatal in approximately one-third of the 135 confirmed cases detected in the 4 months following its initial identification [2], and limited human-to-human H7N9 virus transmission could not be excluded in some Chinese clusters of cases [3, 4]. There was, and still is, the possibility that the virus would mutate to the point where there would be sustained human-to-human transmission. Given that most of the human population has no prior immunity (either due to natural challenge or vaccine induced), such a strain presents the danger of starting an influenza pandemic. | In response to such a threat, the Joint Modeling Unit at the Centers for Disease Control and Prevention (CDC) was asked to conduct a rapid assessment of both the potential burden of unmitigated disease and the possible impacts of different mitigation measures. We were tasked to evaluate the 6 following interventions: invasive mechanical ventilators, influenza antiviral drugs for treatment (but not large-scale prophylaxis), influenza vaccines, respiratory protective devices for healthcare workers and surgical face masks for patients, school closings to reduce transmission, and airport-based screening to identify those ill with novel influenza virus entering the United States. This supplement presents reports on the methods and estimates for the first 5 listed interventions, and in this introduction we outline the general approach and standardized epidemiological assumptions used in all the articles. |
2014 MERS-CoV outbreak in Jeddah - a link to health care facilities
Oboho IK , Tomczyk SM , Al-Asmari AM , Banjar AA , Al-Mugti H , Aloraini MS , Alkhaldi KZ , Almohammadi EL , Alraddadi BM , Gerber SI , Swerdlow DL , Watson JT , Madani TA . N Engl J Med 2015 372 (9) 846-54 BACKGROUND: A marked increase in the number of cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection occurred in Jeddah, Saudi Arabia, in early 2014. We evaluated patients with MERS-CoV infection in Jeddah to explore reasons for this increase and to assess the epidemiologic and clinical features of this disease. METHODS: We identified all cases of laboratory-confirmed MERS-CoV infection in Jeddah that were reported to the Saudi Arabian Ministry of Health from January 1 through May 16, 2014. We conducted telephone interviews with symptomatic patients who were not health care personnel, and we reviewed hospital records. We identified patients who were reported as being asymptomatic and interviewed them regarding a history of symptoms in the month before testing. Descriptive analyses were performed. RESULTS: Of 255 patients with laboratory-confirmed MERS-CoV infection, 93 died (case fatality rate, 36.5%). The median age of all patients was 45 years (interquartile range, 30 to 59), and 174 patients (68.2%) were male. A total of 64 patients (25.1%) were reported to be asymptomatic. Of the 191 symptomatic patients, 40 (20.9%) were health care personnel. Among the 151 symptomatic patients who were not health care personnel, 112 (74.2%) had data that could be assessed, and 109 (97.3%) of these patients had had contact with a health care facility, a person with a confirmed case of MERS-CoV infection, or someone with severe respiratory illness in the 14 days before the onset of illness. The remaining 3 patients (2.7%) reported no such contacts. Of the 64 patients who had been reported as asymptomatic, 33 (52%) were interviewed, and 26 of these 33 (79%) reported at least one symptom that was consistent with a viral respiratory illness. CONCLUSIONS: The majority of patients in the Jeddah MERS-CoV outbreak had contact with a health care facility, other patients, or both. This highlights the role of health care-associated transmission. (Supported by the Ministry of Health, Saudi Arabia, and by the U.S. Centers for Disease Control and Prevention.). |
Middle East Respiratory Syndrome-Coronavirus (MERS-CoV): CDC update for clinicians
Rasmussen SA , Gerber SI , Swerdlow DL . Clin Infect Dis 2015 60 (11) 1686-9 Although much recent focus has been on the recognition of Ebola virus disease among travelers from West Africa, cases of Middle East Respiratory Syndrome-Coronavirus (MERS-CoV), including travel-associated cases, continue to be reported. US clinicians need to be familiar with recommendations regarding when to suspect MERS-CoV, how to make a diagnosis, and what infection control measures need to be instituted when a case is suspected. Infection control is especially critical, given that most cases have been health care-associated. Two cases of MERS-CoV were identified in the United States in May of 2014; because these cases were detected promptly and appropriate control measures were put in place quickly, no secondary cases occurred. This paper summarizes information that US clinicians need to know to prevent secondary cases of MERS-CoV from occurring in the US. |
Update on the epidemiology of Middle East respiratory syndrome coronavirus (MERS-CoV) infection, and guidance for the public, clinicians, and public health authorities - January 2015
Rha B , Rudd J , Feikin D , Watson J , Curns AT , Swerdlow DL , Pallansch MA , Gerber SI . MMWR Morb Mortal Wkly Rep 2015 64 (3) 61-2 CDC continues to work with the World Health Organization (WHO) and other partners to closely monitor Middle East respiratory syndrome coronavirus (MERS-CoV) infections globally and to better understand the risks to public health. The purpose of this report is to provide a brief update on MERS-CoV epidemiology and to notify health care providers, public health officials, and others to maintain awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. |
Preparation of at-risk West African countries for Ebola
Vora NM , Arthur RR , Swerdlow DL , Angulo FJ . Lancet 2015 385 (9965) 329-330 The ongoing Ebola epidemic in west Africa is an unprecedented health and humanitarian crisis. So far, more than 20 000 cases have been reported1 in Guinea, Liberia, and Sierra Leone, and transmission models developed during this epidemic have predicted spread of Ebola into neighbouring west African countries.2 These predictions have already been realised in Nigeria and Senegal, but public health authorities in both countries acted swiftly to limit secondary transmission.3, 4 The experiences in Nigeria and Senegal attest to the effectiveness of conventional epidemiological methods—particularly, case isolation and contact tracing—in containing Ebola outside the three countries with widespread transmission.5 Mali became the latest west African country to report an Ebola introduction in October, 2014, followed by another independent introduction in November, 2014, and the country's public health authorities responded efficiently such that the outbreaks have now been contained. Improvement of Ebola preparedness and response capacity in neighbouring at-risk west African countries should therefore be prioritised so that public health responses can be rapidly initiated elsewhere if the need arises. |
Unraveling the mysteries of Middle East respiratory syndrome coronavirus
Watson JT , Hall AJ , Erdman DD , Swerdlow DL , Gerber SI . Emerg Infect Dis 2014 20 (6) 1054-6 Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel CoV known to cause severe acute respiratory illness in humans; ≈40% of confirmed cases have been fatal. Human-to-human transmission and multiple outbreaks of respiratory illness have been attributed to MERS-CoV, and severe respiratory illness caused by this virus continues to be identified. MERS-CoV was first reported in September 2012, and subsequent investigations documented illness onsets as early as April 2012 (1). As of February 23, 2014, the World Health Organization has reported 182 laboratory-confirmed cases of MERS-CoV infection, including 79 deaths, indicating an ongoing risk for transmission to humans in the Arabian Peninsula (2). The median age of reported case-patients is 52 years (range 2–94 years); most case-patients are male (3). Most index case-patients have at least 1 reported chronic comorbid condition (4) and have resided in, or recently traveled to, Jordan, Qatar, United Arab Emirates, Oman, Kuwait, or Saudi Arabia (3). Confirmed cases of MERS-CoV have been identified in travelers returning from France, Germany, Italy, United Kingdom, and Tunisia (3). Although some have speculated that a zoonotic reservoir of MERS-CoV exists, very little is known about the specific exposures that result in primary human cases. | MERS-CoV infection causes severe acute hypoxemic respiratory failure, extrapulmonary organ dysfunction, and high rates of death; however, the spectrum of illness and clinical course are not fully defined (5). Evidence suggests that MERS-CoV is capable of limited human-to-human transmission, which results in outbreaks in family and health care settings (5,6). The 182 reported cases include multiple distinct spatiotemporal clusters and 32 identified infections in health care workers (3). Modeling performed to assess the extent of human infection and the transmission potential of MERS-CoV (as of August 2013) estimated that most symptomatic case-patients had not been detected but that chains of transmission were not self-sustaining when infection control was implemented (7). Despite evidence of human-to-human transmission, the number of contacts infected by persons with confirmed infections appears to be limited; sustained transmission in the community has not been documented (3). The Hajj, the annual religious pilgrimage to Saudi Arabia, involved 1.37 million pilgrims from 188 countries in 2013 but resulted in no reports of confirmed cases in the weeks after the pilgrimage (3). |
Hospital-associated outbreak of Middle East respiratory syndrome coronavirus: a serologic, epidemiologic, and clinical description
Al-Abdallat MM , Payne DC , Alqasrawi S , Rha B , Tohme RA , Abedi GR , Al Nsour M , Iblan I , Jarour N , Farag NH , Haddadin A , Al-Sanouri T , Tamin A , Harcourt JL , Kuhar DT , Swerdlow DL , Erdman DD , Pallansch MA , Haynes LM , Gerber SI . Clin Infect Dis 2014 59 (9) 1225-33 BACKGROUND: In April 2012, the Jordan Ministry of Health (JMoH) investigated an outbreak of lower respiratory illnesses at a hospital in Jordan; two fatal cases were retrospectively confirmed by rRT-PCR to be the first detected cases of Middle East Respiratory Syndrome (MERS-CoV). METHODS: Epidemiologic and clinical characteristics of selected potential cases were assessed through serum blood specimens, medical chart reviews and interviews with surviving outbreak members, household contacts, and healthcare personnel. Cases of MERS-CoV infection were identified using three U.S. Centers for Disease Control and Prevention (CDC) serologic tests for detection of anti-MERS-CoV antibodies. RESULTS: Specimens and interviews were obtained from 124 subjects. Seven previously unconfirmed individuals tested positive for anti-MERS-CoV antibodies by at least two of three serologic tests, in addition to two fatal cases identified by rRT-PCR. The case fatality rate among the nine total cases was 22%. Six cases were healthcare workers at the outbreak hospital, yielding an attack rate of 10% among potentially exposed outbreak hospital personnel. There was no evidence of MERS-CoV transmission at two transfer hospitals having acceptable infection control practices. CONCLUSION: Novel serological tests allowed for the detection of otherwise unrecognized cases of MERS-CoV infection among contacts of a Jordan hospital-associated respiratory illness outbreak in April 2012, resulting in a total of nine test-positive cases. Serologic results suggest that further spread of this outbreak to transfer hospitals did not occur. Most cases had no major, underlying medical conditions; none were on hemodialysis. Our observed case fatality was lower than has been reported from outbreaks elsewhere. |
First confirmed cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection in the United States, updated information on the epidemiology of MERS-CoV infection, and guidance for the public, clinicians, and public health authorities - May 2014
Bialek SR , Allen D , Alvarado-Ramy F , Arthur R , Balajee A , Bell D , Best S , Blackmore C , Breakwell L , Cannons A , Brown C , Cetron M , Chea N , Chommanard C , Cohen N , Conover C , Crespo A , Creviston J , Curns AT , Dahl R , Dearth S , DeMaria A , Echols F , Erdman DD , Feikin D , Frias M , Gerber SI , Gulati R , Hale C , Haynes LM , Heberlein-Larson L , Holton K , Ijaz K , Kapoor M , Kohl K , Kuhar DT , Kumar AM , Kundich M , Lippold S , Liu L , Lovchik JC , Madoff L , Martell S , Matthews S , Moore J , Murray LR , Onofrey S , Pallansch MA , Pesik N , Pham H , Pillai S , Pontones P , Poser S , Pringle K , Pritchard S , Rasmussen S , Richards S , Sandoval M , Schneider E , Schuchat A , Sheedy K , Sherin K , Swerdlow DL , Tappero JW , Vernon MO , Watkins S , Watson J . MMWR Morb Mortal Wkly Rep 2014 63 (19) 431-6 Since mid-March 2014, the frequency with which cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have been reported has increased, with the majority of recent cases reported from Saudi Arabia and United Arab Emirates (UAE). In addition, the frequency with which travel-associated MERS cases have been reported and the number of countries that have reported them to the World Health Organization (WHO) have also increased. The first case of MERS in the United States, identified in a traveler recently returned from Saudi Arabia, was reported to CDC by the Indiana State Department of Health on May 1, 2014, and confirmed by CDC on May 2. A second imported case of MERS in the United States, identified in a traveler from Saudi Arabia having no connection with the first case, was reported to CDC by the Florida Department of Health on May 11, 2014. The purpose of this report is to alert clinicians, health officials, and others to increase awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. This report summarizes recent epidemiologic information, provides preliminary descriptions of the cases reported from Indiana and Florida, and updates CDC guidance about patient evaluation, home care and isolation, specimen collection, and travel as of May 13, 2014. |
National patterns of Escherichia coli O157 infections, USA, 1996-2011
Sodha SV , Heiman K , Gould LH , Bishop R , Iwamoto M , Swerdlow DL , Griffin PM . Epidemiol Infect 2014 143 (2) 1-7 US public health laboratories began reporting Escherichia coli O157 isolates to CDC in 1996. We describe temporal and geographical patterns of isolates reported from 1996 to 2011 and demographics of persons whose specimens yielded isolates. We calculated annual E. coli O157 isolation rates/100 000 persons by patient's state of residence, county of residence, age, and sex using census data. The average annual isolation rate was 0.84. The average isolation rate in northern states (1.52) was higher than in southern states (0.43). Counties with 76% rural population had a lower isolation rate (0.67) than counties with 25%, 26-50%, and 51-75% rural populations (0.81, 0.92, and 0.81, respectively). The highest isolation rate (3.19) was in children aged 1-4 years. Infections were seasonal with 49% of isolates collected during July to September. Research into reasons for higher incidence in northern states and for seasonality could guide strategies to prevent illnesses. |
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