BACKGROUND: This manuscript describes an updated spreadsheet tool that sexually transmitted infection (STI) prevention programs in the United States can use to estimate the health and economic benefits of their STI and HIV prevention activities. METHODS: The development of the updated tool, STIC (Sexually Transmitted Infection Costs) Figure 2.0, involved two main components. First, we revised the tool to be more useful and user-friendly based on feedback from focus groups and usability testing. Second, we updated the mathematical model behind the calculations by (1) revising the model to reflect current STI and HIV prevention activities in the United States, (2) updating the epidemiological and economic parameters in the model using the best available evidence, and (3) including ranges (not just point estimates) in the model output. To demonstrate the use of STIC Figure 2.0, we applied it to estimate the impact of a hypothetical prevention program, consistent with that of a health department or large STI clinic in a metropolitan area. RESULTS: STIC Figure 2.0 incorporated new features, including an interactive user interface to explore findings and create customized charts for use in reports and presentations. The hypothetical example we analyzed illustrated how providing STI treatment to 2,680 people and HIV prevention services to 325 people could avert 1,253 adverse outcomes and save over $2 million in medical costs and productivity costs. CONCLUSIONS: Although subject to important limitations, STIC Figure 2.0 allows state and local programs, including STI clinics, to calculate evidence-based estimates of the impact of their program activities.

COVID-19 vaccination averted approximately 68,000 hospitalizations during the 2023-24 respiratory season. In June 2024, CDC and the Advisory Committee on Immunization Practices (ACIP) recommended that all persons aged ≥6 months receive a 2024-2025 COVID-19 vaccine, which targets Omicron JN.1 and JN.1-derived sublineages. Interim effectiveness of 2024-2025 COVID-19 vaccines was estimated against COVID-19-associated emergency department (ED) or urgent care (UC) visits during September 2024-January 2025 among adults aged ≥18 years in one CDC-funded vaccine effectiveness (VE) network, against COVID-19-associated hospitalization in immunocompetent adults aged ≥65 years in two networks, and against COVID-19-associated hospitalization among adults aged ≥65 years with immunocompromising conditions in one network. Among adults aged ≥18 years, VE against COVID-19-associated ED/UC visits was 33% (95% CI = 28%-38%) during the first 7-119 days after vaccination. Among immunocompetent adults aged ≥65 years from two CDC networks, VE estimates against COVID-19-associated hospitalization were 45% (95% CI = 36%-53%) and 46% (95% CI = 26%-60%) during the first 7-119 days after vaccination. Among adults aged ≥65 years with immunocompromising conditions in one network, VE was 40% (95% CI = 21%-54%) during the first 7-119 days after vaccination. These findings demonstrate that vaccination with a 2024-2025 COVID-19 vaccine dose provides additional protection against COVID-19-associated ED/UC encounters and hospitalizations compared with not receiving a 2024-2025 dose and support current CDC and ACIP recommendations that all persons aged ≥6 months receive a 2024-2025 COVID-19 vaccine dose.

OBJECTIVE: Using an innovative data sharing model, we assessed the impacts of the COVID-19 pandemic on the health of people who inject drugs (PWID). DESIGN: The PWID Data Collaborative was established in 2021 to promote data sharing across PWID studies in North America. Contributing studies submitted aggregate data on 23 standardized indicators during four time periods: prepandemic (March 2019 to February 2020), early-pandemic (March 2020 to February 2021), mid-pandemic (March 2021 to February 2022), and late pandemic (March 2022 to February 2023). METHODS: We present study-specific and meta-analyzed estimates for the percentage of PWID who took medications for opioid use disorder, received substance use treatment, shared syringes or injection equipment, had a mental health condition, had been incarcerated, or had experienced houselessness. To examine change over time across indicators, we fit a random effects meta-regression model to prevalence estimates using time as a moderator. RESULTS: Thirteen studies contributed estimates to the Data Collaborative on these indicators, representing 6213 PWID interviews. We observed minimal change across prevalence of the six indicators between the prepandemic (March 2019 to February 2020) and three subsequent time periods, overall or within individual studies. Considerable heterogeneity was observed across study-specific and time-specific estimates. CONCLUSION: Limited pandemic-related change observed in indicators of PWID health is likely a result of policy and supportive service-related changes and may also reflect resilience among service providers and PWID themselves. The Data Collaborative is an unprecedented data sharing model with potential to greatly improve the quality and timeliness of data on the health of PWID.

To understand how coronavirus disease 2019 vaccines impact infection risk in children <5 years, we assessed risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection from September 2022 to April 2023 in 3 cohort studies. There was no difference in risk by vaccination status. While vaccines reduce severe disease, they may not reduce SARS-CoV-2 infections in naïve young children.

Purpose: To investigate the prevalence, patterns, and predictors of SARS-CoV-2 RNA and culturable virus in tears of a case-ascertained household cohort. Design: Prospective, longitudinal case-ascertained household cohort identified through convenience sampling. MethodsThis analysis was restricted to individuals who were non-hospitalized, symptomatic, and tested positive for SARS-CoV-2 by nasal RT-PCR. Tears and anterior nasal biospecimens were serially collected throughout the acute period. Tears specimens were collected by the study staff using Schirmer test strips, and nasal specimens were self-collected. For both, SARS-CoV-2 RNA was quantified using qRT-PCR, and culturable virus was detected using presence of cytopathic effect (CPE) in tissue culture; positive CPE was confirmed by a qRT-PCR step. A series of cross-sectional unadjusted analyses were performed investigating the relationship between different sociodemographic determinants and biological factors associated with tears RNA positivity.

The introduction of the Sustainable Development Goals by the United Nations has set a global target for achieving Universal Health Coverage, requiring resilient health systems capable of addressing public health emergencies and ensuring health security. Public health surveillance, crucial for detecting and responding to infectious disease outbreaks, is key to building health system resilience. Due to the high levels of mobility and political instability in the Middle East and North Africa (MENA) region, unique challenges arise in cross-border health surveillance. This review aims to highlight the importance of cross-border public health surveillance in strengthening health systems across MENA to achieve equitable health outcomes.A mixed-methods approach was utilized, combining a systematic literature review with semi-structured in-depth interviews (IDIs) involving 28 stakeholders from seven MENA countries. The literature review adhered to PRISMA guidelines, while the IDIs provided qualitative insights into current surveillance practices and challenges. Findings from the literature review and IDIs were triangulated and analyzed using the WHO Health Systems Strengthening (HSS) Building Blocks Framework to identify key challenges and recommendations for improving cross-border surveillance.Results indicate that existing cross-border surveillance systems in MENA face challenges in data collection, analysis, and sharing, with disparities across countries based on income levels and political contexts. Key challenges include delayed and incomplete data sharing, insufficient funding across sectors, inadequate training, inconsistent data definitions, and limited integration of health data for mobile populations. Recommendations emphasize strengthened governance and leadership to facilitate regional cooperation and information sharing, sustainable financing for implementing a One Health approach, utilizing innovative information systems, workforce development to enhance data collection and analysis, and secure supply chains for medicines and vaccines and equitable service delivery for all mobile populations.In conclusion, the WHO HSS Building Block Framework provides a comprehensive approach to assessing and improving cross-border public health surveillance and enhancing health security and equity in MENA. Strengthening cross-border surveillance systems may help MENA countries meet IHR requirements, achieve greater health security, and advance health equity among all types of mobile populations. Despite limitations, the study offers critical insights for improving cross-border surveillance strategies in the region.

To assess the prevalence of several parasitic infections in Kiribati, dried blood spots collected during trachoma prevalence surveys in the two major population centers in 2015, 2016, and 2019 were tested using multiplex bead-based serologic assays to detect IgG antibodies against four pathogens of public health interest: Toxoplasma gondii (T. gondii), Taenia solium (T. solium), Strongyloides stercoralis (S. stercoralis), and Toxocara canis (T. canis). In Kiritimati Island, the seroprevalences of T. solium recombinant antigen for detection of cysticercosis antibodies (T24H) and recombinant antigen for detection of taeniasis antibodies (ES33) were ≤4% in both surveys, whereas in Tarawa, the T24H seroprevalence was 2% (2016) and 7% (2019) and the ES33 seroprevalence was ≤3% in both surveys. At both sites, the seropositivity of S. stercoralis recombinant antigen for detection of Strongyloides was 0-4%, and for T. canis, the C-type lectin-1 antigen was 0-1% in all surveys. For T. gondii, the surface antigen glycoprotein 2A antigen seroprevalences on Kiritimati Island were 41% (2015) and 36% (2019), and in Tarawa, they were 36% (2016) and 22% (2019), suggesting that T. gondii infections are common in Kiribati, whereas the other pathogens are not.

Zika virus (ZIKV) is a flavivirus transmitted primarily by the bite of infected Aedes species mosquitoes. Although typically asymptomatic or causing mild symptoms and infrequent neurological disease in older children and adults, infection during pregnancy can result in severe congenital malformations and neurodevelopmental deficits. We conducted a review of published literature and official data sources to describe recent Zika epidemiological trends, building on WHO updates posted in 2019 and 2022. Globally, cases declined after the height of ZIKV transmission in the Americas in 2015-2016; however, transmission continues across multiple regions, with intermittent outbreaks reported. As of December 2023, there is documented evidence of current or prior autochthonous mosquito-borne ZIKV transmission in 92 countries and territories; most recently, Guinea, Mali, and Sri Lanka were included on the basis of recent or retrospective testing of specimens collected during surveillance activities or studies. The abundance of asymptomatic and mild infections and limited diagnostic testing suggest that transmission in many locations likely remains underrecognized. Public health authorities, clinicians, communities at risk, and travelers should remain alert to the possibility of ZIKV transmission and implement measures to limit the risk of infection with ZIKV and other Aedes-borne arboviruses. To strengthen surveillance for ZIKV infections and congenital disease, targeted surveillance using clear case definitions and epidemiologically appropriate laboratory testing algorithms should be applied.

Influenza causes 100,000-710,000 hospitalizations annually in the U.S. Patients with liver disease are at higher risk of severe outcomes following influenza infection. This study evaluated influenza vaccine effectiveness (VE) against influenza-associated hospitalization among adults with liver disease. Data from the U.S. Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN), a test-negative case-control study, from 2015 to 2020 were used to estimate VE among adults ≥18 years admitted for acute respiratory illness. VE was calculated as (1-adjusted odds ratio)*100%, comparing the odds of vaccine receipt between laboratory-confirmed influenza cases and test-negative controls using multiple logistic regression with inverse probability of treatment weighting (IPTW). In total, 1,622 (12.8%) of 12,704 adults had ≥1 liver disease(s). Compared with those without liver disease, adults with liver disease were more likely to be admitted to the intensive care unit (15.7% vs 12.8%, p = .001) or to die in hospital (3.0% vs 1.4%, p < .001). The IPTW-adjusted VE against influenza-associated hospitalization was 27% (95% confidence interval [CI], 22-32%) among patients without liver disease, but the VE of 11% (95% CI, -8-26%) was not significant among those with liver disease. Significant effect modification of VE by the presence of liver disease was found (p < .05 for interaction term). While influenza vaccination significantly reduced the risk of influenza-associated hospitalization among adults without liver disease, the protective effect was not significant among those with liver disease. Further studies are warranted to evaluate influenza VE in patients with different types of liver disease and with specific vaccine formulations. | Using a test-negative, case-control study, we observed that influenza vaccination was associated with a significantly lower risk of influenza-associated hospitalization among adults without liver disease, but the protective effect was not significant among those with liver disease. | eng

We assessed severe acute respiratory syndrome coronavirus 2 seroprevalence on residual blood samples for pediatric COVID-19 surveillance: 2263 samples were collected during routine outpatient visits (<18 years, April 2020-August 2021). Seroprevalence increased over time, coinciding with or preceding virus circulation in the community and with or preceding pediatric severe COVID-19 hospitalization peaks. Residual blood sample seroprevalence may be a useful surveillance tool in future outbreaks.

BACKGROUND: The 2023-24 U.S. influenza season was characterized by a predominance of A(H1N1)pdm09 virus circulation with co-circulation of A(H3N2) and B/Victoria viruses. We estimated vaccine effectiveness (VE) in the United States against mild-to-moderate medically attended influenza illness in the 2023-24 season. METHODS: We enrolled outpatients aged ≥8 months with acute respiratory illness in 7 states. Respiratory specimens were tested for influenza type/subtype by reverse-transcriptase polymerase chain reaction (RT-PCR). Influenza VE was estimated with a test-negative design comparing odds of testing positive for influenza among vaccinated versus unvaccinated participants. We estimated VE by virus sub-type/lineage and A(H1N1)pdm09 genetic subclades. RESULTS: Among 6,589 enrolled patients, 1,770 (27%) tested positive for influenza including 796 A(H1N1)pdm09, 563 B/Victoria, and 323 A(H3N2). Vaccine effectiveness against any influenza illness was 41% (95% Confidence Interval [CI]: 32 to 49): 28% (95% CI: 13 to 40) against influenza A(H1N1)pdm09, 68% (95% CI: 59 to 76) against B/Victoria, and 30% (95% CI: 9 to 47) against A(H3N2). Statistically significant protection against any influenza was found for all age groups except adults aged 50-64 years. Lack of protection in this age group was specific to influenza A-associated illness. We observed differences in VE by birth cohort and A(H1N1)pdm09 virus genetic subclade. CONCLUSIONS: Vaccination reduced outpatient medically attended influenza overall by 41% and provided protection overall against circulating influenza A and B viruses. Serologic studies would help inform differences observed by age groups.

BACKGROUND: Understanding protection against SARS-CoV-2 infection by vaccine and hybrid immunity is important for informing public health strategies as new variants emerge. METHODS: We analyzed data from three cohort studies spanning September 1, 2022-July 31, 2023, to estimate COVID-19 vaccine effectiveness (VE) against SARS-CoV-2 infection and symptomatic COVID-19 among adults with and without prior infection in the United States. Participants collected weekly nasal swabs, irrespective of symptoms, annual blood draws, and completed periodic surveys, which included vaccination status and prior infection history. Swabs were tested molecularly for SARS-CoV-2. VE was estimated using Cox proportional hazards models for the hazard ratios of infections, adjusting for covariates. VE was calculated considering prior infection and recency of vaccination. RESULTS: Among 3,344 adults, adjusted VE of bivalent vaccine against infection was 37.2% (95% CI: 12.3-55.7%) within 7-59 days of vaccination and 21.1% (95% CI: -0.5-37.1%) within 60-179 days of vaccination compared to participants who were unvaccinated/received an original monovalent vaccine dose ≥180 days prior. Overall, adjusted VE of bivalent vaccine against infection, in conjunction with prior infection, was 62.2% (95% CI: 46.0-74.5%) within 7-179 days of vaccination and 39.4% (95% CI: 12.5-61.6%) ≥180 days compared to naïve participants who were unvaccinated/received a monovalent vaccine dose ≥180 days prior. CONCLUSIONS: Adults with both prior infection and recent vaccination had high protection against infection and symptomatic illness. Recent vaccination alone provided moderate protection.

During 2023, the Centers for Disease Control and Prevention (CDC) recommended the first respiratory syncytial virus (RSV) immunizations intended for widespread use in the United States to prevent severe RSV illness in infants and older adults. CDC, in collaboration with federal, public health, and academic partners, is conducting evaluations of real-world effectiveness of recommended RSV immunization products in the United States. Similar frameworks for evaluation are being applied to RSV vaccines and nirsevimab, a long-acting preventative monoclonal antibody, to estimate product effectiveness. The overall goal of CDC's RSV immunization effectiveness program is to generate timely and robust evidence through observational studies to inform immunization product policy decisions and other measures related to RSV prevention and control. CDC is evaluating effectiveness through high-quality, well-controlled observational studies leveraging a variety of platforms that provide robust data to inform policy decisions.

OBJECTIVES: Evidence indicates that people living with HIV (PLHIV) are more impacted by COVID-19. The burden of SARS-CoV-2 infection among PLHIV is unknown in Nigeria. METHODS: We conducted repeated cross-sectional SARS-CoV-2 serosurveys in 14 states and the Federal Capital Territory in Nigeria among PLHIV who had an HIV viral load (VL) test during April 2022 to January 2023. Evidence of SARS-CoV-2 immunoglobulin G (IgG) antibodies was assessed using a multiplex bead assay to measure IgG to spike (S), receptor binding domain (RBD), and nucleocapsid (N) proteins to identify potential infection and/or vaccination status. RESULTS: Between April 2022 and January 2023, 47,614 remnant VL samples were included and tested for SARS-CoV-2 antibodies. Seroprevalence of SARS-CoV-2 infection, defined as IgG antibodies to spike and RBD591 [S+] and nucleocapsid [N+], (S+N+), ranged between 21.1% (95% confidence intervals [CI]: 11.4-31.8) in Ekiti State in January 2023 to 71.4% (95% CI 71.9-81.9) in Gombe State in November 2022, with overall steady trends within and between states over time, across age and sex. CONCLUSION: High rates of SARS-CoV-2 antibody seroprevalence among PLHIV in Nigeria were observed. This underscores the need to understand the association between HIV and SARS-CoV-2 to inform strategies to reduce the threat posed by COVID-19.

BACKGROUND: A recent infection testing algorithm (RITA) incorporating case surveillance (CS) with the rapid test for recent HIV infection (RTRI) was integrated into HIV testing services in Thailand as a small-scale pilot project in October 2020. OBJECTIVE: We aimed to describe the lessons learned and initial outcomes obtained after the establishment of the nationwide recent HIV infection surveillance project from April through August 2022. METHODS: We conducted desk reviews, developed a surveillance protocol and manual, selected sites, trained staff, implemented surveillance, and analyzed outcomes. Remnant blood specimens of consenting newly diagnosed individuals were tested using the Asanté HIV-1 Rapid Recency Assay. The duration of HIV infection was classified as RTRI-recent or RTRI-long-term. Individuals testing RTRI-recent with CD4 counts <200 cells/mm3 or those having opportunistic infections were classified as RITA-CS-long-term. Individuals testing RTRI-recent with CD4 counts >200 cells/mm3, no opportunistic infections, and not on antiretroviral treatment were classified as RITA-CS-recent. RESULTS: Two hundred and one hospitals in 14 high-burden HIV provinces participated in the surveillance. Of these, 69 reported ≥1 HIV diagnosis during the surveillance period. Of 1053 newly diagnosed cases, 64 (6.1%) were classified as RITA-CS-recent. On multivariate analysis, self-reporting as transgender women (adjusted odds ratio [AOR] 7.41, 95% CI 1.59-34.53) and men who have sex with men (AOR 2.59, 95% CI 1.02-6.56) compared to heterosexual men, and students compared to office workers or employers (AOR 3.76, 95% CI 1.25-11.35) were associated with RITA-CS-recent infection. The proper selection of surveillance sites, utilizing existing surveillance tools and systems, and conducting frequent follow-up and supervision visits were the most commonly cited lessons learned to inform the next surveillance phase. CONCLUSIONS: Recent HIV infection surveillance can provide an understanding of current epidemiologic trends to inform HIV prevention interventions to interrupt ongoing or recent HIV transmission. The key success factors of the HIV recent infection surveillance in Thailand include a thorough review of the existing HIV testing service delivery system, a streamlined workflow, strong laboratory and health services, and regular communication between sites and the Provincial Health Offices.

Little is known about the epidemiology of leptospirosis in the Dominican Republic, the second most populous country in the Caribbean. We report on findings from a multi-stage household survey across two regions in the country that reveals a previously under-estimated burden of human Leptospira infection. Our findings, based on the reference-standard microscopic agglutination test, indicate a complex picture of serogroup diversity, spatial heterogeneity in infection and risk, and a marked discrepancy between reported cases and serologically estimated infections. Given an overall seroprevalence of 11.3% (95% CI: 10.8-13.0%) and a lower estimated force of infection (0.30% per year [0.27%-0.35%]) the number of infections may exceed national reported case data by 145-fold or more. Icterohaemorrhagiae, associated with severe Weil's disease, was the most commonly identified serogroup with a serogroup-specific prevalence of 4.4%. Consistent with other settings, risk factors including age, male sex, and rat exposure were associated with higher seroprevalence. Our study highlights the need for targeted public health interventions informed by serogroup-specific dynamics, detailed spatial analyses, knowledge of local animal reservoirs, and strengthened laboratory surveillance to effectively control this pathogen.

BACKGROUND: Indoor residual spraying (IRS) is a malaria control strategy implemented before the rainy season. Nchelenge District, Zambia is a holoendemic setting where IRS has been conducted since 2008 with little impact on malaria incidence or parasite prevalence. Pre-rainy season IRS may not reduce the post-rainy season peak abundance of the major vector, Anopheles funestus. METHODS: A controlled, pre-post, prospective cohort study assessed the impact of late-rainy season IRS on malaria prevalence, incidence, hazard, and vector abundance. Three hundred eighty-two individuals were enrolled across four household clusters, of which two were sprayed in April 2022 toward the end of the rainy season. Monthly household and individual surveys and indoor overnight vector collections were conducted through August 2022. Multivariate regression and time-to-event analyses estimated the impact of IRS on outcomes measured by rapid diagnostic tests, microscopy, and quantitative polymerase chain reaction. RESULTS: Seventy two percent of participants tested positive by rapid diagnostic test at least once and incidence by microscopy was 3.4 infections per person-year. Residing in a household in a sprayed area was associated with a 52% reduction in infection hazard (hazards ratio: 0.48, 95% confidence interval [0.29, 0.78]) but not with changes in incidence, prevalence, or vector abundance. The study-wide entomological inoculation rate was 34 infectious bites per person per year. CONCLUSION: Monthly tracking of incidence and prevalence did not demonstrate meaningful changes in holoendemic transmission intensity. However, hazard of infection, which provides greater power for detecting changes in transmission, demonstrated that late rainy season IRS reduced malaria risk.

To understand how COVID-19 vaccines impact infection risk in children <5 years, we assessed risk of SARS-CoV-2 infection from Sept 2022-April 2023 in three cohort studies. There was no difference in risk by vaccination status. While vaccines reduce severe disease, they may not reduce SARS-CoV-2 infections in young children.

The global landscape of professional training in environmental health, encompassing ecological public health or environmental public health, lacks consistent global implementation for training programs for public health practitioners, clinical professionals, and individuals across various disciplines, as well as standardized curricula for undergraduates. This training gap is related to the overall lack of capacity in addressing the population impacts of the triple challenge of pollution, biodiversity loss, and climate change, impeding the worldwide transition to and development of ecological sustainability. This paper reviews existing approaches and their potential to address implementation challenges within the necessarily tight timescale. Spreading of best practice appears feasible even without substantial additional resources, through the reorientation of current practices via comprehensive multi-disciplinary training programs. By adopting international best practices of training in environmental health, the focus in training and education can shift from future decision-makers to enhancing the competencies of current professionals and their institutions.

Unsustainable globalisation of economic activities, lifestyles and social structures has contributed to environmental degradation, posing major threats to human health at the local and global levels. All these problems including climate change, pollution, and biodiversity loss represent challenges that are unlikely to be met with existing approaches, capabilities and tools. This article acknowledges the need for well-prepared practitioners from many walks of life to contribute to environmental public health (EPH) functions thus strengthening society's capacity and capability to respond effectively and in a timely manner to such complex situations and multiple challenges. It envisions a new EPH practice addressing questions on: Why do this? What needs to be addressed? Who will do it? How can it be implemented? This article focuses on the main challenging EPH issues worldwide and how they could be addressed using a conceptual framework for training. A companion article shows how they have been tackled in practice, providing ideas and experiences.

BACKGROUND: Trachoma programs use the indicator trachomatous inflammation--follicular (TF) to monitor indication for and response to treatment for trachoma at the district level. Alternative indicators, including serologic markers, are increasingly being evaluated for trachoma surveillance. We evaluated seroprevalence of IgG antibodies to the Pgp3 antigen in two districts in Maradi, Niger thought to have low TF prevalence. METHODS: Data were collected as part of the baseline assessment of the Azithromycin Reduction to Reach Elimination of Trachoma (ARRET) trial in September 2021. A random sample of 80 communities was selected from Mayahi and Guidan Roumdji districts, both of which had TF prevalence <20% at their most recent trachoma impact survey in 2018. A random sample of 50 children per community was sampled. We collected field grades, conjunctival swabs for processing PCR for ocular Chlamydia trachomatis, and dried blood spots for serologic assessment. RESULTS: Of 3,994 children sampled in 80 communities, 49% were female and median age was 4 years. Overall TF prevalence was 4.6% (95% CI 3.5 to 5.8%) and trachomatous inflammation-intense (TI) prevalence was 0.6% (95% 0.3 to 0.9%). The prevalence of ocular chlamydia was 0.03% (95% CI 0.08%). Seroprevalence for Pgp3 antibodies was 6.3% (95% CI 5.5 to 7.1%) in 1-9-year-olds and 3.7% (95% CI 2.9 to 4.4%) in 1-5-year-olds. TF and Pgp3 seroprevalence were better correlated in 1-5-year-olds (correlation coefficient 0.29) compared to 1-9-year-olds (correlation coefficient 0.09). CONCLUSIONS: In this low trachoma prevalence setting in Niger, seroprevalence of antibodies to Pgp3 were consistent with little ongoing transmission of C. trachomatis.

OBJECTIVES: Trivalent inactivated influenza vaccine effectiveness was low in a prospective cohort of healthcare personnel (HCP) in Israel from 2016 to 2019. We conducted a randomised immunogenicity trial of quadrivalent recombinant influenza vaccine (RIV4) and standard-dose inactivated influenza vaccine (IIV4) among frequently and infrequently vaccinated previous cohort participants. METHODS: From October 2019 to January 2020, we enrolled and randomly allocated HCP from two Israeli hospitals to receive IIV4 or RIV4. Hemagglutination inhibition (HAI) antibody titres against 2019-2020 vaccine reference influenza viruses were compared between vaccine groups using geometric mean titre (GMT) ratios from sera collected one-month post-vaccination and by frequency of vaccination in the past 5 years (>2 vs ≤2). RESULTS: Among 415 HCP, the GMT ratio comparing RIV4 to IIV4 was 2.0 (95% confidence interval [CI] 1.7-2.7) for A(H1N1)pdm09, 1.6 (95% CI: 1.3-1.9) for A(H3N2), 1.8 (95% CI: 1.4-2.2) for B(Yamagata), and 1.1 (95% CI: 0.9-1.4) for B(Victoria). Similarly, RIV4 elicited higher HAI titres than IIV4 against all 2019-2020 vaccine reference viruses except B(Victoria) among infrequently and frequently vaccinated HCP (lower bound of GMT ratio 95% CIs ≥1.0). CONCLUSION: RIV4 had improved immunogenicity for influenza vaccine strains among both infrequent and frequent vaccinees compared to standard-dose IIV4. CLINICAL TRIALS REGISTRATION: NCT04523324.

BACKGROUND: In test-negative studies of vaccine effectiveness (VE), including patients with co-circulating, vaccine-preventable, respiratory pathogens in the control group for the pathogen of interest can introduce a downward bias on VE estimates. METHODS: A multicenter sentinel surveillance network in the US prospectively enrolled adults hospitalized with acute respiratory illness from September 1, 2022-March 31, 2023. We evaluated bias in estimates of VE against influenza-associated and COVID-19-associated hospitalization based on: inclusion vs exclusion of patients with a co-circulating virus among VE controls; observance of VE against the co-circulating virus (rather than the virus of interest), unadjusted and adjusted for vaccination against the virus of interest; and observance of influenza or COVID-19 against a sham outcome of respiratory syncytial virus (RSV). RESULTS: Overall VE against influenza-associated hospitalizations was 6 percentage points lower when patients with COVID-19 were included in the control group, and overall VE against COVID-19-associated hospitalizations was 2 percentage points lower when patients with influenza were included in the control group. Analyses of VE against the co-circulating virus and against the sham outcome of RSV showed that downward bias was largely attributable the correlation of vaccination status across pathogens, but also potentially attributable to other sources of residual confounding in VE models. CONCLUSION: Excluding cases of confounding respiratory pathogens from the control group in VE analysis for a pathogen of interest can reduce downward bias. This real-world analysis demonstrates that such exclusion is a helpful bias mitigation strategy, especially for measuring influenza VE, which included a high proportion of COVID-19 cases among controls.

Test-negative design (TND) studies are cornerstones of vaccine effectiveness (VE) monitoring for influenza. The introduction of SARS-CoV-2 and RSV vaccines complicate the analysis of this design, with control selection restriction based on other pathogen diagnosis proposed as a solution. We conducted a simulation study and secondary analysis of 2017-18 and 2018-19 TND estimates from a Southeast Michigan ambulatory population to evaluate RSV-status-based control restriction. Simulations suggest that with vaccine-preventable RSV, influenza VE could be moderately biased with RSV prevalence ≥25 % of controls. Real-world analysis showed 151 influenza-negative adults (10.4 %) had RSV detected from the enrollment nasal swab. There were minimal differences in results of adjusted models with or without RSV exclusion from control groups. Findings suggest that inclusion of RSV cases in the control group of TND studies for influenza VE, particularly where RSV is not vaccine preventable, does not currently pose a major concern for bias in VE estimates.

While influenza A virus (IAV) antigenic drift has been documented globally, in experimental animal infections, and in immunocompromised hosts, positive selection has generally not been detected in acute infections. This is likely due to challenges in distinguishing selected rare mutations from sequencing error, a reliance on cross-sectional sampling, and/or the lack of formal tests of selection for individual sites. Here, we sequenced IAV populations from 346 serial, daily nasal swabs from 143 individuals collected over three influenza seasons in a household cohort. Viruses were sequenced in duplicate, and intrahost single nucleotide variants (iSNVs) were identified at a 0.5% frequency threshold. Within-host populations exhibited low diversity, with >75% mutations present at <2% frequency. Children (0-5 years) had marginally higher within-host evolutionary rates than adolescents (6-18 years) and adults (>18 years, 4.4 × 10(-6) vs. 9.42 × 10(-7) and 3.45 × 10(-6), P < .001). Forty-five iSNVs had evidence of parallel evolution but were not over-represented in HA and NA. Several increased from minority to consensus level, with strong linkage among iSNVs across segments. A Wright-Fisher approximate Bayesian computational model identified positive selection at 23/256 loci (9%) in A(H3N2) specimens and 19/176 loci (11%) in A(H1N1)pdm09 specimens, and these were infrequently found in circulation. Overall, we found that within-host IAV populations were subject to genetic drift and purifying selection, with only subtle differences across seasons, subtypes, and age strata. Positive selection was rare and inconsistently detected.

Swine harbors a genetically diverse population of swine influenza A viruses (IAV-S), with demonstrated potential to transmit to the human population, causing outbreaks and pandemics. Here, we describe the development of a one-step, triplex real-time reverse transcription-polymerase chain reaction (rRT-PCR) assay that detects and distinguishes the majority of the antigenically distinct influenza A virus hemagglutinin (HA) clades currently circulating in North American swine, including the IAV-S H1 1A.1 (α), 1A.2 (β), 1A.3 (γ), 1B.2.2 (δ1) and 1B.2.1 (δ2) clades, and the IAV-S H3 2010.1 clade. We performed an in-field test at an exhibition swine show using in-field viral concentration and RNA extraction methodologies and a portable real-time PCR instrument, and rapidly identified three distinct IAV-S clades circulating within the N.A. swine population. Portable sequencing is used to further confirm the results of the in-field test of the swine triplex assay. The IAV-S triplex rRT-PCR assay can be easily transported and used in-field to characterize circulating IAV-S clades in North America, allowing for surveillance and early detection of North American IAV-S with human outbreak and pandemic potential.

Single-dose doxycycline after high-risk tick bites can prevent Lyme disease, which disproportionately affects children. We described single-dose doxycycline dispensings in an outpatient cohort in the United States. During 2010-2020, a total of 427 105 patients received ≥1 dispensing(s); most were aged ≥65 years. Lyme disease postexposure prophylaxis may be underprescribed for some groups, including children.

Oropouche virus has recently caused outbreaks in South America and the Caribbean, expanding into areas to which the virus was previously not endemic. This geographic range expansion, in conjunction with the identification of vertical transmission and reports of deaths, has raised concerns about the broader threat this virus represents to the Americas. We review information on Oropouche virus, factors influencing its spread, transmission risk in the United States, and current status of public health response tools. On the basis of available data, the risk for sustained local transmission in the continental United States is considered low because of differences in vector ecology and in human-vector interactions when compared with Oropouche virus-endemic areas. However, more information is needed about the drivers for the current outbreak to clarify the risk for further expansion of this virus. Timely detection and control of this emerging pathogen should be prioritized to mitigate disease burden and stop its spread.

BACKGROUND: Clostridioides difficile infection (CDI) may be misdiagnosed if testing is performed in the absence of signs or symptoms of disease. This study sought to support appropriate testing by estimating the impact of signs, symptoms, and healthcare exposures on pre-test likelihood of CDI. METHODS: A panel of fifteen experts in infectious diseases participated in a modified UCLA/RAND Delphi study to estimate likelihood of CDI. Consensus, defined as agreement by >70% of panelists, was assessed via a REDCap survey. Items without consensus were discussed in a virtual meeting followed by a second survey. RESULTS: All fifteen panelists completed both surveys (100% response rate). In the initial survey, consensus was present on 6 of 15 (40%) items related to risk of CDI. After panel discussion and clarification of questions, consensus (>70% agreement) was reached on all remaining items in the second survey. Antibiotics were identified as the primary risk factor for CDI and grouped into three categories: high-risk (likelihood ratio [LR] 7, 93% agreement among panelists in first survey), low-risk (LR 3, 87% agreement in first survey), and minimal-risk (LR 1, 71% agreement in first survey). Other major factors included new or unexplained severe diarrhea (e.g., ≥ 10 liquid bowel movements per day; LR 5, 100% agreement in second survey) and severe immunosuppression (LR 5, 87% agreement in second survey). CONCLUSION: Infectious disease experts concurred on the importance of signs, symptoms, and healthcare exposures for diagnosing CDI. The resulting risk estimates can be used by clinicians to optimize CDI testing and treatment.

Mozambique is making progress towards elimination of trachoma as a public health problem, but in some districts trachomatous inflammation-follicular (TF) prevalence remains above the 5% elimination threshold despite years of various interventions, including antibiotic mass drug administration. To characterize transmission in four districts, we incorporated testing of ocular infection and serology into routine trachoma impact surveys (TIS) in August 2022. We examined residents aged ≥ 1 year for trachoma and collected information on household water, sanitation, and hygiene. Among children aged 1-9 years, we tested conjunctival swabs for Chlamydia trachomatis nucleic acid and dried blood spots for C. trachomatis antibodies. We modeled age-dependent seroprevalence to estimate seroconversion rate (SCR). We examined 4841 children aged 1-9 years. TF prevalence ranged between 1.1 and 6.0% with three districts below the 5% threshold. PCR-confirmed infection prevalence ranged between 1.1 and 4.8%, and Pgp3 seroprevalence ranged between 8.8 and 24.3%. Pgp3 SCR was 1.9 per 100 children per year in the district with the lowest TF prevalence. Two other districts with TF < 5% had SCR of 5.0 and 4.7. The district with TF ≥ 5% had a SCR of 6.0. This enhanced TIS furthered understanding of transmission in these districts and provides information on additional indicators for monitoring trachoma programs.