Nirsevimab is a long-acting monoclonal antibody that protects infants and young children against severe respiratory syncytial virus (RSV) disease. Children are eligible for one 50 mg dose, one 100 mg dose, or two 100 mg doses of nirsevimab based on age, weight, time of year, maternal vaccination, and risk of severe disease. In winter 2023/2024, we developed a model to project the number of nirsevimab doses needed to immunize all eligible U.S. children during the 2024/2025 season. We grouped all births from March 2023 through March 2025 into weekly cohorts, partitioned those cohorts based on eligibility criteria, and computed eligibility for each partition. In the absence of maternal RSV vaccination, we estimated U.S. children would be eligible to receive 4.3 million nirsevimab doses in 2024/2025, of which 48% would be 100 mg doses. Projections of total eligibility can be used to inform production goals and avoid shortages of nirsevimab.

BACKGROUND: Influenza vaccine effectiveness can be reduced in older adults and among repeatedly vaccinated groups. Results from year 1 of "PIVOT," a randomized trial among adults aged ≥65 years in Hong Kong, showed that adjuvanted (Adj), high-dose (HD), and recombinant hemagglutinin (rHA) vaccines induced greater antibody responses against vaccine viruses than standard-dose (SD) influenza vaccine. Here, we examine the breadth of A(H3N2)-reactive antibodies induced during the first 2 study years (2017/2018, 2018/2019), and compare participants who received influenza vaccination annually, or not at all, for 5 years preceding enrollment. METHODS: 14-20 PIVOT participants per vaccine and prior vaccination group (0/5 or 5/5 prior years) who provided sera on days 0, 30, and 182 in year 1 and days 0 and 30 in year 2 were assessed. Hemagglutination inhibition (HAI) antibody titers were measured against 30 viruses spanning 1968 to 2018. RESULTS: In year 1, rHA and Adj but not HD vaccines induced titers ≥40 and titer rises ≥4-fold (seroconversion) against significantly more strains than SD vaccine among participants vaccinated 0/5 prior years. Only rHA and Adj vaccines induced titers ≥40 against post-vaccine strains. Antibody responses were poor among participants vaccinated 5/5 compared with 0/5 prior years and only rHA increased the breadth of seroconversion compared with the SD vaccine in this group. Antibody responses were weaker across groups in year 2. CONCLUSIONS: The results suggest that Adj and particularly rHA vaccines may improve the breadth of protection against A(H3N2) viruses but may not overcome attenuating effects of repeated vaccination in older adults. CLINICAL TRIALS REGISTRATION: NCT03330132.

Antimicrobial resistance (AMR) is an urgent threat to public health, but gaps in surveillance limit the detection of emergent novel threats and knowledge about the global distribution of AMR genes. International travelers frequently acquire AMR organisms, and thus may provide a window into AMR dynamics in otherwise poorly monitored regions and environments. To assess the utility of travelers as global AMR sentinels, we collected pre- and post-travel stool samples from 608 travelers, which were screened for the presence of extended-spectrum beta-lactamase producing Enterobacterales, carbapenem-resistant Enterobacterales, and mcr-mediated colistin-resistant Enterobacterales. A total of 307 distinct AMR organisms were sequenced in order to determine genotypic patterns and their association with travel region and behavior. Travel-associated AMR organisms were overwhelmingly E. coli, which exhibited considerable phylogenetic diversity regardless of travel region. However, the prevalence of resistance genes varied by region, with bla (CTX-M-55) and bla (CTX-M-27) significantly more common in travelers returning from South America and South-Eastern Asia, respectively. Hybrid assembly and plasmid reconstruction revealed the genomic neighborhood of bla (CTX-M-55) frequently matched a motif previously linked to animal populations. Contact with animals was also associated with virulence factors in acquired AMR organisms, including carriage of the ColV plasmid, a driver of avian pathogenic E. coli. We identified novel variants of the mcr-1 gene in strains acquired from Western Africa, highlighting the potential for traveler surveillance to detect emerging clinical threats. Ongoing efforts to track travel-acquired organisms could complement existing global AMR surveillance frameworks.

A Rocky Mountain spotted fever (RMSF) epidemic has spread through the state of Baja California, Mexico over the last decade and a half, beginning in Mexicali, and subsequently to Tijuana and to Ensenada by 2018. In October of 2022, we surveyed dogs and homes in randomly selected Áreas Geoestadisticas Básicas (AGEBs) with and without reported human cases. Brown dog ticks (Rhipicephalus sanguineus sensu lato) were found on 33.9% of dogs and in the yards of 23.6% of homes. Homes from AGEBs with cases had over a 6-fold increased odds of ticks being present in the yard than AGEBs without reported cases. Both dogs that were permitted to roam and the presence of roaming dogs in the neighborhood were strongly associated with tick infestation of dogs and homes. No ticks or blood samples were polymerase chain reaction-positive for Rickettsia (R.) rickettsii, the causative agent of RMSF, although 54.6% of dogs were seropositive for spotted fever group rickettsiae, and 17.4% were seropositive for typhus group rickettsiae. R. massiliae and R. felis were detected in eight (1.3%) and 29 (4.8%) ticks, respectively; and R. felis was also detected in eight (4.6%) dog blood samples. Although the pathogenic potential of these other rickettsial species and their role in RMSF transmission remains unclear, our data on tick burdens in dogs and homes as risk factors for RMSF exposure provide further support to the pivotal need to reduce tick burdens and the numbers of roaming dogs to successfully manage the RMSF epidemic in northern Mexico.

BACKGROUND: The 2022 mpox outbreak in the United States disproportionately affected gay, bisexual, and other men who have sex with men (GBMSM). Uptake of mpox testing may be related to symptomology, sociodemographic characteristics, and behavioral characteristics. OBJECTIVE: This study aimed to describe suspected mpox symptoms and testing uptake among a sample of GBMSM recruited via the internet in the United States in August 2022. METHODS: We conducted a rapid internet-based mpox survey from August 5 to 15, 2022, among cisgender men 15 years and older who had previously participated in the 2021 American Men's Internet Survey. We estimated the prevalence of suspected mpox symptoms (fever or rash or sores with unknown cause in the last 3 mo) and uptake of mpox testing. We calculated adjusted prevalence ratios (aPRs) and 95% CIs for associations between participant characteristics and suspected mpox symptoms and summarized characteristics of GBMSM reporting mpox testing. Among symptomatic GBMSM who did not receive mpox testing, we described testing self-efficacy, barriers, and facilitators. RESULTS: Of 824 GBMSM, 126 (15.3%) reported at least 1 mpox symptom in the last 3 months; 58/126 (46%) with rash or sores, 57 (45.2%) with fever, and 11 (8.7%) with both. Increased prevalence of suspected mpox symptoms was associated with condomless anal sex (CAS; aPR 1.53, 95% CI 1.06-2.20). Mpox testing was reported by 9/824 GBMSM (1%), including 5 with symptoms. Most GBMSM reporting mpox testing were non-Hispanic White men (7/9 vs 1 Black and 1 Hispanic or Latino man), and all 9 lived in urban areas. Most reported having an sexually transmitted infections test (8/9), 2 or more partners (8/9), CAS (7/9), and group sex (6/9) in the last 3 months. Of those tested, 3 reported living with HIV and all were on treatment, whereas the remaining 6 men without HIV reported current pre-exposure prophylaxis (PrEP) use. Of symptomatic GBMSM who did not report mpox testing, 47/105 (44.8%) had low mpox testing self-efficacy. Among those with low self-efficacy, the most common barriers to testing were not knowing where to get tested (40/47, 85.1%) and difficulty getting appointments (23/47, 48.9%). Among those with high testing self-efficacy (58/105, 55.2%), the most common facilitators to testing were knowing where to test (52/58, 89.7%), convenient site hours (40/58, 69%), and low-cost testing (38/58, 65.5%). CONCLUSIONS: While all GBMSM who reported testing for mpox were linked to HIV treatment or PrEP, those with symptoms but no mpox testing reported fewer such links. This suggests targeted outreach is needed to reduce structural barriers to mpox services among GBMSM in rural areas, Black and Hispanic or Latino GBMSM, and GBMSM living with HIV. Sustaining and scaling community-tailored messaging to promote testing and vaccination represent critical interventions for mpox control among GBMSM in the United States.

Mosquito-transmitted viruses such as dengue are a global and growing public health challenge. Without widely available vaccines, mosquito control is the primary tool for fighting the spread of these viruses. New mosquito control technologies are needed to complement existing methods, given current challenges with scalability, acceptability, and effectiveness. A field trial was conducted in collaboration with the Communities Organized to Prevent Arboviruses project in Ponce, Puerto Rico, to measure entomological and epidemiological effects of reducing Aedes aegypti populations using Wolbachia incompatible insect technique. We packed and shipped Wolbachia-males from California and released them into 19 treatment clusters from September 2020 to December 2020. Preliminary evaluation revealed sub-optimal Wolbachia-male densities and impact on the wild-type population. In 2021, we shifted to a phased release strategy starting in four clusters, reducing the mosquito population by 49% (CI 29-63%). We describe the investigation into male quality and other factors that may have limited the impact of Wolbachia-male releases. Laboratory assays showed a small but significant impact of packing and shipping on male fitness. However, mark-release-recapture assessments suggest that male daily survival rates in the field may have been significantly impacted. We compared induced-sterility levels and suppression of the wild population and found patterns consistent with mosquito population compensation in response to our intervention. Analysis of epidemiological impact was not possible due to very low viral transmission rates during the intervention period. Our entomological impact data provide evidence that Wolbachia incompatible-male releases reduced Ae. aegypti populations, although efficacy will be maximized when releases are part of an integrated control program. With improvement of shipping vessels and shipped male fitness, packing and shipping male mosquitoes could provide a key solution for expanding access to this technology. Our project underscores the challenges involved in large and complex field effectiveness assessments of novel vector control methods.

BACKGROUND: Dengue virus, a major global health threat, consists of four serotypes (DENV1-4) that cause a range of clinical manifestations from mild to severe and potentially fatal disease. METHODS: This study, based on 19 years of data from the Pediatric Dengue Cohort Study and Pediatric Dengue Hospital-based Study in Managua, Nicaragua, investigates the relationship of serotype and immune status with dengue severity. Dengue cases were confirmed by molecular, serological, and/or virological methods, and study participants 6 months to 17 years old were followed during their hospital stay or as ambulatory patients. RESULTS: We enrolled a total of 15,833 participants, of whom 3,308 (21%) were positive for DENV infection. Of 2,644 cases with serotype result by RT-PCR, 559 corresponded to DENV1, 1,002 to DENV2, 760 to DENV3 and 323 to DENV4. Severe disease was more prevalent among secondary DENV2 and DENV4 cases, while similar disease severity was observed in both primary and secondary DENV1 and DENV3 cases. According to the 1997 World Health Organization (WHO) severity classification, both DENV2 and DENV3 caused a higher proportion of severe disease compared to other serotypes, whereas DENV3 caused the greatest percentage of severity according to the WHO-2009 classification. DENV2 was associated with increased odds of pleural effusion and low platelet count, while DENV3 was associated with both hypotensive and compensated shock. CONCLUSIONS: These findings demonstrate differences in dengue severity by serotype and immune status and emphasize the critical need for a dengue vaccine with balanced effectiveness against all four serotypes, particularly as existing vaccines show variable efficacy by serotype and serostatus.

We assessed mpox vaccine communication and sexual behavior among U.S. MSM during the 2022 mpox outbreak. Less than 40% of respondents asked a new male sex partner about their mpox vaccination status. Mpox vaccine communication was positively associated with condomless anal sex and group sex. Mpox vaccine communication is low but may inform and sexual behaviors among MSM.

OBJECTIVE: To determine whether differences exist in antibiotic prescribing for respiratory infections in pediatric urgent cares (PUCs) by patient race/ethnicity, insurance, and language. DESIGN: Multi-center cohort study. SETTING: Nine organizations (92 locations) from 22 states and Washington, DC. PARTICIPANTS: Patients ages 6 months-18 years evaluated April 2022-April 2023, with acute viral respiratory infections, otitis media with effusion (OME), acute otitis media (AOM), pharyngitis, community-acquired pneumonia (CAP), and sinusitis. METHODS: We compared the use of first-line (FL) therapy as defined by published guidelines. We used race/ethnicity, insurance, and language as exposures. Multivariable logistic regression models estimated the odds of FL therapy by group. RESULTS: We evaluated 396,340 ARI encounters. Among all encounters, 351,930 (88.8%) received FL therapy (98% for viral respiratory infections, 85.4% for AOM, 96.0% for streptococcal pharyngitis, 83.6% for sinusitis). OME and CAP had the lowest rates of FL therapy (49.9% and 60.7%, respectively). Adjusted odds of receiving FL therapy were higher in Black Non-Hispanic (NH) (adjusted odds ratio [aOR] 1.53 [1.47, 1.59]), Asian NH (aOR 1.46 [1.40, 1.53], and Hispanic children (aOR 1.37 [1.33, 1.41]), compared to White NH. Additionally, odds of receiving FL therapy were higher in children with Medicaid/Medicare (aOR 1.21 [1.18-1.24]) and self-pay (aOR 1.18 [1.1-1.27]) compared to those with commercial insurance. CONCLUSIONS: This multicenter collaborative showed lower rates of FL therapy for children of the White NH race and those with commercial insurance compared to other groups. Exploring these differences through a health equity lens is important for developing mitigating strategies.

OBJECTIVE: The 2019 European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) systemic lupus erythematosus (SLE) classification criteria score (≥20 points) has been associated with poor outcomes. We aimed to evaluate its utility as a predictor for mortality and hospitalisation and to derive and validate an ominosity score based on the SLE classification criteria set. METHODS: Incident patients with SLE in a population-based cohort were included. The association between the 2019 EULAR/ACR SLE score and mortality and hospitalisation was assessed using Cox regression adjusted for age, sex and calendar year. An ominosity score for mortality was developed based on the SLE criteria set. The least absolute shrinkage and selection operator method was used to estimate model coefficients. Concordance and calibration were assessed by cross-validation and by plotting the observed event rates against the deciles of predicted probabilities. RESULTS: Among 374 patients with incident SLE, a EULAR/ACR score ≥20 points was not associated with an increased risk of mortality (HR 1.17, 95% CI 0.67 to 2.03) or first hospitalisation (HR 1.14, 95% CI 0.79 to 1.64) compared with a score ≤19 points. The derived ominosity score for mortality included age, sex, thrombocytopaenia, neuropsychiatric manifestations, subacute cutaneous or discoid lupus, non-scarring alopecia, inflammatory arthritis, renal involvement, antiphospholipid antibodies and hypocomplementaemia. This model demonstrated a concordance=0.76 with adequate calibration. Age and sex were the main predictors, as seen in the model including just age, sex and year (concordance=0.77). CONCLUSION: The 2019 EULAR/ACR SLE criteria score was not associated with mortality and hospitalisation. The derived ominosity score for mortality presented good prediction for mortality but was not better than age and sex alone.

BACKGROUND AND OBJECTIVES: Respiratory syncytial virus (RSV) causes substantial hospitalization in US infants. The Advisory Committee on Immunization Practices recommended nirsevimab in infants younger than 8 months born during or entering their first RSV season and for children aged 8 to 19 months at increased risk of RSV hospitalization in their second season. This study's objective was to evaluate the cost-effectiveness of nirsevimab in all infants in their first RSV season and in high-risk children in their second season. METHODS: We simulated healthcare utilization and deaths from RSV with and without nirsevimab among infants aged 0 to 7 months and those 8 to 19 months old over a single RSV season. Data came from published literature, US Food and Drug Administration approval documents, and epidemiologic surveillance data. We evaluated societal outcomes over a lifetime discounting at 3% and reporting in 2022 US dollars. Sensitivity and scenario analyses identified influential variables. RESULTS: We estimated that 107 253 outpatient visits, 38 204 emergency department visits, and 14 341 hospitalizations could be averted each year if half of the US birth cohort receives nirsevimab. This would cost $153 517 per quality-adjusted life year (QALY) saved. Nirsevimab in the second season for children facing a 10-fold higher risk of hospitalization would cost $308 468 per QALY saved. Sensitivity analyses showed RSV hospitalization costs, nirsevimab cost, and QALYs lost from RSV disease were the most influential parameters with cost-effectiveness ratios between cost-saving and $323 788 per QALY saved. CONCLUSIONS: Nirsevimab for infants may be cost-effective, particularly among those with higher risks and costs of RSV.

BACKGROUND AND OBJECTIVES: Respiratory syncytial virus (RSV) commonly causes hospitalization among US infants. A maternal vaccine preventing RSV in infants, RSV bivalent prefusion F maternal vaccine (RSVpreF), was approved by the US Food and Drug Administration and recommended by the Advisory Committee on Immunization Practices. Our objective was to evaluate the health benefits and cost-effectiveness of vaccinating pregnant persons in the United States using RSVpreF. METHODS: We simulated RSV infection and disease with and without seasonal RSVpreF vaccination in half of the pregnant persons in the annual US birth cohort during weeks 32 through 36 of gestation. Model inputs came from peer-reviewed literature, Food and Drug Administration records, and epidemiological surveillance databases. The results are reported using a societal perspective in 2022 US dollars for a 1-year time frame, discounting future health outcomes and costs at 3%. Sensitivity and scenario analyses were performed. RESULTS: Year-round maternal vaccination with RSVpreF would prevent 45 693 outpatient visits, 15 866 ED visits, and 7571 hospitalizations among infants each year. Vaccination had a societal incremental cost of $396 280 per quality-adjusted life-year (QALY) saved. Vaccination from September through January cost $163 513 per QALY saved. The most influential inputs were QALYs lost from RSV disease, the cost of the vaccine, and RSV-associated hospitalization costs; changes in these inputs yielded outcomes ranging from cost-saving to $800 000 per QALY saved. CONCLUSIONS: Seasonal maternal RSV vaccination designed to prevent RSV lower respiratory tract infection in infants may be cost-effective, particularly if administered to pregnant persons immediately before or at the beginning of the RSV season.

Rocky Mountain spotted fever (RMSF) is an ongoing public health crisis in Mexico, particularly in states bordering the United States. The national highest incidence and mortality of RMSF occur in this region, resulting in a case-fatality rate that ranges annually between 10% and 50%, primarily affecting vulnerable groups such as children, elderly adults, and persons living in poverty. Multiple biological, environmental, and social determinants can explain its growing presence throughout the country and how it challenges the health system and society. It is necessary to integrate resources and capacities from health authorities, research centers, and society to succeed in dealing with this problem. Through a scientific symposium, a group of academicians, U.S. health officials, and Mexican health authorities met on November 8-10, 2023, in Hermosillo, Mexico, to discuss the current situation of RMSF across the country and the challenges associated with its occurrence. An urgent call for action to improve national capacity against RMSF in the aspects of epidemiological and acarological surveillance, diagnosis, medical care, case and outbreak prevention, health promotion, and research was urged by the experts. The One Health approach is a proven multidisciplinary strategy to integrate policies and interventions to mitigate and prevent the burden of cases, deaths, and suffering caused by RMSF in Mexico.

OBJECTIVE: To characterize presentation and care pathways of patients with systemic lupus erythematosus (SLE), and delays in access to SLE-specialized care. METHODS: We included patients with incident SLE from the Lupus Midwest Network registry. Time from the first medical encounter for SLE clinical manifestation to access to SLE-specialized care, physician diagnosis, and treatment was estimated. Delays were defined as ≥6 months to access specialized care. We compared SLE manifestations, disease activity (SLEDAI-2k), and SLICC/ACR damage indexes (SDI) between patients with and without delays. Logistic regression models assessed associations with delays. RESULTS: The study included 373 patients with SLE. The median time to access SLE-specialized care was 1.1 months (95% confidence interval [CI] 0.9-1.5); time to diagnosis 30.6 months (95% CI 18.9-48.1), and time to treatment initiation 4.7 months (95% CI 3.9-8.4). Approximately 25% (93/373) of patients experienced delays accessing specialized care, which were associated with fewer SLE manifestations at first SLE-related encounter (<2 SLE domains; 92% vs 72%, P < 0.001). Patients with mucocutaneous or musculoskeletal manifestations were less likely to experience delays, while hematologic (odds ratio [OR] 1.71, 95% CI 1.03-2.84) or antiphospholipid antibodies domains (OR 6.05, 95% CI 2.46-14.88) were associated with delays. Delays were associated with damage at first access to SLE-specialized care (SDI ≥1; 30% vs 7%, P < 0.001). CONCLUSIONS: Patients follow a heterogeneous pathway to receive care. One-fourth of patients experienced delays accessing SLE-specialized care, which was associated with damage. Fewer manifestations, hematologic, or antiphospholipid antibodies were associated with delays.

BACKGROUND: Individual immune responses to SARS-CoV-2 are well-studied, while the combined effect of these responses on population-level immune dynamics remains poorly understood. Given the key role of population immunity on pathogen transmission, delineation of the factors that drive population immune evolution has critical public health implications. METHODS: We enrolled individuals 5 years and older selected using a multistage cluster survey approach in the Northwest and Southeast of the Dominican Republic. Paired blood samples were collected mid-pandemic (Aug 2021) and late pandemic (Nov 2022). We measured serum pan-immunoglobulin antibodies against the SARS-CoV-2 spike protein. Generalized Additive Models (GAMs) and random forest models were used to analyze the relationship between changes in antibody levels and various predictor variables. Principal component analysis and partial dependence plots further explored the relationships between predictors and antibody changes. FINDINGS: We found a transformation in the distribution of antibody levels from an irregular to a normalized single peak Gaussian distribution that was driven by titre-dependent boosting. This led to the convergence of antibody levels around a common immune setpoint, irrespective of baseline titres and vaccination profile. INTERPRETATION: Our results suggest that titre-dependent kinetics driven by widespread transmission direct the evolution of population immunity in a consistent manner. These findings have implications for targeted vaccination strategies and improved modeling of future transmission, providing a preliminary blueprint for understanding population immune dynamics that could guide public health and vaccine policy for SARS-CoV-2 and potentially other pathogens. FUNDING: The study was primarily funded by the Centers for Disease Control and Prevention grant U01GH002238 (EN). Salary support was provided by Wellcome Trust grant 206250/Z/17/Z (AK) and the Australian National Health and Medical Research Council Investigator grant APP1158469 (CLL).

INTRODUCTION: This research aims to characterize disparities in mpox- and vaccine-related knowledge in gay, bisexual, and other men who have sex with men in the U.S. METHODS: The authors conducted a study using the American Men's Internet Survey, which includes 823 cisgender (defined as their gender identity matching their sex assigned at birth) males aged ≥15 years from August 5 to 15, 2022. The authors evaluated sociodemographic and behavioral factors associated with mpox knowledge, including race/ethnicity, region, age group, and HIV pre-exposure prophylaxis use using chi-square tests. RESULTS: The authors identified knowledge gaps, with many participants unsure about whether individuals need 2 doses of the vaccine (34.4%) and whether the vaccine confers immediate protection (27.2%). The authors observed racial and regional disparities (p<0.01), with 24.4% of non-Hispanic Black men and 18.1% of men living in the South reporting little to no mpox awareness. Among the 707 self-reported HIV-negative participants, people who used pre-exposure prophylaxis within the past year were more likely to exhibit high awareness about mpox than people who did not use pre-exposure prophylaxis. CONCLUSIONS: Findings suggest the potential to leverage existing networks (i.e., sexually transmitted infection or general health care services with pre-exposure prophylaxis use) for future targeted health service programming or education campaigns for mpox vaccination among gay, bisexual, and other men who have sex with men.

INTRODUCTION: We evaluated internet platforms for distributing HIV self-tests (HIVSTs) to Black or African American (Black) and Hispanic or Latino men who have sex with men (MSM) and transgender women (TGW). METHODS: We recruited MSM and TGW from general interest, dating, and lesbian, gay, bisexual, and transgender platforms. Two HIVSTs were mailed to all MSM and TGW. Surveys (screening, baseline, 4-month, and results reporting) were completed online. After 4 months, participants were mailed another HIVST and a dried blood spot card. All HIVST interpretations and images of HIVST devices were reported online. RESULTS: Of 2093 MSM and 102 TGW, most were recruited through general interest and dating platforms. Over 50% were 18-29 years old, most identified as gay or bisexual. Overall, 45% had not tested for HIV in the past 12 months, and 9.1% of MSM reported a positive (reactive for HIV antibodies) HIVST result, with the highest percentage among Black MSM (11.5%). Dating platforms recruited higher percentages of MSM who recorded positive results compared with MSM from general interest platforms during the intervention period (11.9% vs 5.5% (P < 0.0001)), and MSM who had never tested for HIV reported a greater percentage of positive HIVST results compared with MSM who had been tested for HIV before enrollment (16.1% vs. 7.1%; P < 0.0001). MSM were able to correctly interpret and report HIVST results. Of TGW, 7% reported a positive HIVST result. CONCLUSIONS: Internet dating and general interest platforms can be key to increasing awareness of infection among BMSM, HMSM, and TGW persons, including those who do not use existing HIV services. TRIAL REGISTRATION: www.clinicaltrials.gov Identifier: NCT04219878.

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults. In May 2023, two subunit RSV vaccines (Arexvy [GSK] and Abrysvo [Pfizer]) received approval from the U.S. Food and Drug Administration (FDA). In June 2023, ACIP recommended that adults aged ≥60 years may receive a single dose of RSV vaccine, using shared clinical decision-making. In support of development of this policy, our objective was to assess the cost-effectiveness of RSV vaccination in the general population in this age group. We used a decision-analytical model of RSV over a two-year timeframe using data from published literature, FDA documents, epidemiological databases, and manufacturer data. We tracked RSV-associated outpatient, emergency department, inpatient healthcare utilization, RSV-attributable deaths, quality-adjusted life-years lost (QALYs), and societal costs. The societal cost per QALY saved from RSV vaccination depended on age group and product: adults aged ≥60 years, $196,842 for GSK's vaccine and $176,557 for Pfizer's vaccine; adults ≥65 years, $162,138 for GSK and $146,543 for Pfizer; adults 60- <65 years, $385,829 for GSK and $331,486 for Pfizer. Vaccine efficacy, incidence of RSV hospitalization, and vaccine cost had the greatest influence on cost per QALY. Cost per QALY saved decreased as the age of those vaccinated increased. Inputs such as long-term efficacy are uncertain. RSV vaccination in adults aged ≥60 years may be cost-effective, particularly in those of more advanced age. Lower vaccine acquisition costs and persistent efficacy beyond two RSV seasons would render RSV vaccination more cost-effective for a broader target population. PRIMARY FUNDING SOURCE: US Centers for Disease Control and Prevention.

BACKGROUND: Better understanding differences associated with antibiotic prescribing for acute sinusitis can help inform antibiotic stewardship strategies. We characterized antibiotic prescribing patterns for acute sinusitis among commercially insured adults and explored differences by patient- and prescriber-level factors. METHODS: Outpatient encounters among adults aged 18 to 64 years diagnosed with sinusitis between 2016 and 2020 were identified by national administrative claims data. We classified antibiotic agents-first-line (amoxicillin-clavulanate or amoxicillin) and second-line (doxycycline, levofloxacin, or moxifloxacin)-and ≤7-day durations as guideline concordant based on clinical practice guidelines. Modified Poisson regression was used to examine the association between patient- and prescriber-level factors and guideline-concordant antibiotic prescribing. RESULTS: Among 4 689 850 sinusitis encounters, 53% resulted in a guideline-concordant agent, 30% in a guideline-discordant agent, and 17% in no antibiotic prescription. About 75% of first-line agents and 63% of second-line agents were prescribed for >7 days, exceeding the length of therapy recommended by clinical guidelines. Adults with sinusitis living in a rural area were less likely to receive a prescription with guideline-concordant antibiotic selection (adjusted risk ratio [aRR], 0.92; 95% CI, .92-.92) and duration (aRR, 0.77; 95% CI, .76-.77). When compared with encounters in an office setting, urgent care encounters were less likely to result in a prescription with a guideline-concordant duration (aRR, 0.76; 95% CI, .75-.76). CONCLUSIONS: Opportunities still exist to optimize antibiotic agent selection and treatment duration for adults with acute sinusitis, especially in rural areas and urgent care settings. Recognizing specific patient- and prescriber-level factors associated with antibiotic prescribing can help inform antibiotic stewardship interventions.

BACKGROUND: The COVID-19 pandemic underscored the need for rapid and accurate diagnostic tools. In August 2020, the Abbott BinaxNOW COVID-19 Antigen Card test became available as a timely and affordable alternative for SARS-CoV-2 molecular testing, but its performance may vary due to factors including timing and symptomatology. This study evaluates BinaxNOW diagnostic performance in diverse epidemiological contexts. METHODS: Using RT-PCR as reference, we assessed performance of the BinaxNOW COVID-19 test for SARS-CoV-2 detection in anterior nasal swabs from participants of two studies in Puerto Rico from December 2020 to May 2023. Test performance was assessed by days post symptom onset, collection strategy, vaccination status, symptomatology, repeated testing, and RT-PCR cycle threshold (Ct) values. RESULTS: BinaxNOW demonstrated an overall sensitivity of 84.1% and specificity of 98.8%. Sensitivity peaked within 1-6 days after symptom onset (93.2%) and was higher for symptomatic (86.3%) than asymptomatic (67.3%) participants. Sensitivity declined over the course of infection, dropping from 96.3% in the initial test to 48.4% in testing performed 7-14 days later. BinaxNOW showed 99.5% sensitivity in participants with low Ct values (≤ 25) but lower sensitivity (18.2%) for participants with higher Cts (36-40). CONCLUSIONS: BinaxNOW demonstrated high sensitivity and specificity, particularly in early-stage infections and symptomatic participants. In situations where test sensitivity is crucial for clinical decision-making, nucleic acid amplification tests are preferred. These findings highlight the importance of considering clinical and epidemiological context when interpreting test results and emphasize the need for ongoing research to adapt testing strategies to emerging SARS-CoV-2 variants.

OBJECTIVE: The effects of sanitation and hygiene interventions on the gut microbiome and enteric pathogen burden are not well understood. We measured the association between free chlorine residue (FCR) levels in drinking water, microbiome composition, and stool enteric pathogens in infants and young children in Haiti. METHODS: FCR levels were measured in household drinking water and enteric pathogen burden was evaluated using multiplex RT-PCR of stool among 131 children from one month to five years of age living in Mirebalais, Haiti. Microbiome profiling was performed using metagenomic sequencing. RESULTS: Most individuals lived in households with undetectable FCR measured in the drinking water (112/131, 86%). Detection of enteric pathogen DNA in stool was common and did not correlate with household water FCR. The infant microbiome in households with detectable FCR demonstrated reduced richness (fewer total number of species, P=0.04 Kruskall-Wallis test) and less diversity by Inverse Simpson measures (P=0.05) than households with undetectable FCR. Infants in households with a detectable FCR were more likely to have abundant Bifidobacterium. Using in vitro susceptibility testing, we found that some Bifidobacterium species were resistant to chlorine. CONCLUSIONS: FCR in household drinking water did not correlate with enteric pathogen burden in our study.

While costs of norovirus acute gastroenteritis (AGE) to healthcare systems have been estimated, out-of-pocket and indirect costs incurred by households are not well documented in community settings, particularly in developing countries. We conducted active surveillance for AGE in two communities in Peru: Puerto Maldonado (October 2012-August 2015) and San Jeronimo (April 2015-April 2019). Norovirus AGE events with PCR-positive stool specimens were included. Data collected in follow-up interviews included event-related medical resource utilization, associated out-of-pocket costs, and indirect costs. There were 330 norovirus-associated AGE events among 3,438 participants from 685 households. Approximately 49% of norovirus events occurred among children <5 years of age and total cost to the household per episode was highest in this age group. Norovirus events cost a median of US $2.95 (IQR $1.04-7.85) in out-of-pocket costs and $12.58 (IQR $6.39-25.16) in indirect costs. Medication expenses accounted for 53% of out-of-pocket costs, and productivity losses accounted for 59% of the total financial burden on households. The frequency and associated costs of norovirus events to households in Peruvian communities support the need for prevention strategies including vaccines. Norovirus interventions targeting children <5 years of age and their households may have the greatest economic benefit.

COVID-19, caused by the SARS-CoV-2 virus, is a highly pathogenic emerging infectious disease. Healthcare personnel (HCP) are presumably at higher risk of acquiring emerging infections because of occupational exposure. The prevalence of COVID-19 in HCP is unknown, particularly in low- to middle-income countries like El Salvador. The goal of this study was to determine the seroprevalence of anti-SARS-CoV-2 antibodies among HCP in El Salvador just prior to vaccine rollout in March 2021. We evaluated 2176 participants from a nationally representative sample of national healthcare institutions. We found 40.4% (n = 880) of the study participants were seropositive for anti-spike protein antibodies. Significant factors associated with infection included younger age; living within the central, more populated zone of the country; living in a larger household (≥7 members); household members with COVID-19 or compatible symptoms; and those who worked in auxiliary services (i.e., housekeeping and food services). These findings provide insight into opportunities to mitigate SARS-CoV-2 risk and other emerging respiratory pathogens in HCP in El Salvador.

In September 2022, CDC funded a nationwide program, Together TakeMeHome (TTMH), to expand distribution of HIV self-tests (HIVSTs) directly to consumers by mail through an online ordering portal. To publicize the availability of HIVSTs to priority audiences, particularly those disproportionately affected by HIV, CDC promoted this program through established partnerships and tailored resources from its Let's Stop HIV Together social marketing campaign. The online portal launched March 14, 2023, and through March 13, 2024, distributed 443,813 tests to 219,360 persons. Among 169,623 persons who answered at least one question on a postorder questionnaire, 67.9% of respondents were from priority audiences, 24.1% had never previously received testing for HIV, and 24.8% had not received testing in the past year. Among the subset of participants who initiated a follow-up survey, 88.3% used an HIVST themselves, 27.1% gave away an HIVST, 11.7% accessed additional preventive services, and 1.9% reported a new positive HIVST result. Mailed HIVST distribution can quickly reach large numbers of persons who have never received testing for HIV or have not received testing as often as is recommended. TTMH can help to achieve the goal of diagnosing HIV as early as possible and provides a path to other HIV prevention and care services. Clinicians, community organizations, and public health officials should be aware of HIVST programs, initiate discussions about HIV testing conducted outside their clinics or offices, and initiate follow-up services for persons who report a positive or negative HIVST result.

In Mozambique, targeted provider-initiated HIV testing and counselling (PITC) is recommended where universal PITC is not feasible, but its effectiveness depends on healthcare providers' training. This study aimed to evaluate the effect of a Ministry of Health training module in targeted PITC on the HIV positivity yield, and identify factors associated with a positive HIV test. We conducted a single-group pre-post study between November 2018 and November 2019 in the triage and emergency departments of four healthcare facilities in Manhiça District, a resource-constrained semi-rural area. It consisted of two two-month phases split by a one-week targeted PITC training module ("observation phases"). The HIV positivity yield of targeted PITC was estimated as the proportion of HIV-positive individuals among those recommended for HIV testing by the provider. Additionally, we extracted aggregated health information system data over the four months preceding and following the observation phases to compare yield in real-world conditions ("routine phases"). Logistic regression analysis from observation phase data was conducted to identify factors associated with a positive HIV test. Among the 7,102 participants in the pre- and post-training observation phases (58.5% and 41.5% respectively), 68% were women, and 96% were recruited at triage. In the routine phases with 33,261 individuals (45.8% pre, 54.2% post), 64% were women, and 84% were seen at triage. While HIV positivity yield between pre- and post-training observation phases was similar (10.9% (269/2470) and 11.1% (207/1865), respectively), we observed an increase in yield in the post-training routine phase for women in triage, rising from 4.8% (74/1553) to 7.3% (61/831) (Yield ratio = 1.54; 95%CI: 1.11-2.14). Age (25-49 years) (OR = 2.43; 95%CI: 1.37-4.33), working in industry/mining (OR = 4.94; 95%CI: 2.17-11.23), unawareness of partner's HIV status (OR = 2.50; 95%CI: 1.91-3.27), and visiting a healer (OR = 1.74; 95%CI: 1.03-2.93) were factors associated with a positive HIV test. Including these factors in the targeted PITC algorithm could have increased new HIV diagnoses by 2.6%. In conclusion, providing refresher training and adapting the current targeted PITC algorithm through further research can help reach undiagnosed PLHIV, treat all, and ultimately eliminate HIV, especially in resource-limited rural areas.

BACKGROUND: Little is known about awareness and willingness to use or purchase HIV pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) in Mexico. METHODS: MSM in Mexico were recruited via advertisements on online social venues to participate in Encuesta de Sexo Entre Hombres, an online behavioral survey. Awareness of PrEP, willingness to take PrEP if available for free, willingness to purchase PrEP, awareness of post-exposure prophylaxis (PEP), and ever PEP use were assessed in descriptive and multivariate analyses. RESULTS: Overall, 54.8% (4588/8376) of participants were aware of PrEP. Of those aware, 77.6% were willing to use PrEP if free and 52.6% were willing to purchase PrEP, generally at a maximum monthly cost of $500MXP. Both awareness of and willingness to use PrEP if free or for purchase were significantly greater among MSM who were younger, and varied by demographic, recent healthcare use, and behavioral risk factors. Only 8.2% had ever used PEP, which was highly associated with healthcare utilization. CONCLUSIONS: About half of Mexican MSM were aware of PrEP. The majority of those aware were willing to use PrEP if available for free and many were willing to purchase PrEP at low cost. Leveraging demographic, recent healthcare use, and behavioral risk characteristics associated with awareness and willingness to use PrEP could be useful in designing future PrEP programs for MSM in Mexico. Expanding healthcare settings in which PEP is available may also support identifying candidates for PrEP and scaling up PrEP implementation.

Dengue is the most prevalent mosquito-borne viral disease in humans, and cases are continuing to rise globally. In particular, islands in the Caribbean have experienced more frequent outbreaks, and all four dengue virus (DENV) serotypes have been reported in the region, leading to hyperendemicity and increased rates of severe disease. However, there is significant variability regarding virus surveillance and reporting between islands, making it difficult to obtain an accurate understanding of the epidemiological patterns in the Caribbean. To investigate this, we used travel surveillance and genomic epidemiology to reconstruct outbreak dynamics, DENV serotype turnover, and patterns of spread within the region from 2009-2022. We uncovered two recent DENV-3 introductions from Asia, one of which resulted in a large outbreak in Cuba, which was previously under-reported. We also show that while outbreaks can be synchronized between islands, they are often caused by different serotypes. Our study highlights the importance of surveillance of infected travelers to provide a snapshot of local introductions and transmission in areas with limited local surveillance and suggests that the recent DENV-3 introductions may pose a major public health threat in the region.

BACKGROUND: A better understanding of SARS-CoV-2 infection risk among Hispanic and Latino populations and in low-resource settings in the United States is needed to inform control efforts and strategies to improve health equity. Puerto Rico has a high poverty rate and other population characteristics associated with increased vulnerability to COVID-19, and there are limited data to date to determine community incidence. OBJECTIVE: This study describes the protocol and baseline seroprevalence of SARS-CoV-2 in a prospective community-based cohort study (COPA COVID-19 [COCOVID] study) to investigate SARS-CoV-2 infection incidence and morbidity in Ponce, Puerto Rico. METHODS: In June 2020, we implemented the COCOVID study within the Communities Organized to Prevent Arboviruses project platform among residents of 15 communities in Ponce, Puerto Rico, aged 1 year or older. Weekly, participants answered questionnaires on acute symptoms and preventive behaviors and provided anterior nasal swab samples for SARS-CoV-2 polymerase chain reaction testing; additional anterior nasal swabs were collected for expedited polymerase chain reaction testing from participants that reported 1 or more COVID-19-like symptoms. At enrollment and every 6 months during follow-up, participants answered more comprehensive questionnaires and provided venous blood samples for multiantigen SARS-CoV-2 immunoglobulin G antibody testing (an indicator of seroprevalence). Weekly follow-up activities concluded in April 2022 and 6-month follow-up visits concluded in August 2022. Primary study outcome measures include SARS-CoV-2 infection incidence and seroprevalence, relative risk of SARS-CoV-2 infection by participant characteristics, SARS-CoV-2 household attack rate, and COVID-19 illness characteristics and outcomes. In this study, we describe the characteristics of COCOVID participants overall and by SARS-CoV-2 seroprevalence status at baseline. RESULTS: We enrolled a total of 1030 participants from 388 households. Relative to the general populations of Ponce and Puerto Rico, our cohort overrepresented middle-income households, employed and middle-aged adults, and older children (P<.001). Almost all participants (1021/1025, 99.61%) identified as Latino/a, 17.07% (175/1025) had annual household incomes less than US $10,000, and 45.66% (463/1014) reported 1 or more chronic medical conditions. Baseline SARS-CoV-2 seroprevalence was low (16/1030, 1.55%) overall and increased significantly with later study enrollment time (P=.003). CONCLUSIONS: The COCOVID study will provide a valuable opportunity to better estimate the burden of SARS-CoV-2 and associated risk factors in a primarily Hispanic or Latino population, assess the limitations of surveillance, and inform mitigation measures in Puerto Rico and other similar populations. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/53837.

Meningococcal disease is a life-threatening invasive infection caused by Neisseria meningitidis. Two quadrivalent (serogroups A, C, W, and Y) meningococcal conjugate vaccines (MenACWY) (MenACWY-CRM [Menveo, GSK] and MenACWY-TT [MenQuadfi, Sanofi Pasteur]) and two serogroup B meningococcal vaccines (MenB) (MenB-4C [Bexsero, GSK] and MenB-FHbp [Trumenba, Pfizer Inc.]), are licensed and available in the United States and have been recommended by CDC's Advisory Committee on Immunization Practices (ACIP). On October 20, 2023, the Food and Drug Administration approved the use of a pentavalent meningococcal vaccine (MenACWY-TT/MenB-FHbp [Penbraya, Pfizer Inc.]) for prevention of invasive disease caused by N. meningitidis serogroups A, B, C, W, and Y among persons aged 10-25 years. On October 25, 2023, ACIP recommended that MenACWY-TT/MenB-FHbp may be used when both MenACWY and MenB are indicated at the same visit for the following groups: 1) healthy persons aged 16-23 years (routine schedule) when shared clinical decision-making favors administration of MenB vaccine, and 2) persons aged ≥10 years who are at increased risk for meningococcal disease (e.g., because of persistent complement deficiencies, complement inhibitor use, or functional or anatomic asplenia). Different manufacturers' serogroup B-containing vaccines are not interchangeable; therefore, when MenACWY-TT/MenB-FHbp is used, subsequent doses of MenB should be from the same manufacturer (Pfizer Inc.). This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of MenACWY-TT/MenB-FHbp.