IMPORTANCE: The association of 13-valent pneumococcal conjugate vaccine (PCV13) use with pneumonia hospitalization in older adults, especially those with underlying medical conditions, is not well described. OBJECTIVE: To evaluate the association of PCV13 use with pneumonia, non-health care-associated (non-HA) pneumonia, and lobar pneumonia (LP) hospitalization among US Medicare beneficiaries 65 years or older. DESIGN, SETTING, AND PARTICIPANTS: This cohort study with time-varying exposure assignment analyzed claims data from US Medicare beneficiaries 65 years or older enrolled in Parts A/B with a residence in the 50 US states or the District of Columbia by September 1, 2014. New Medicare Parts A/B beneficiaries within 6 months after their 65th birthday were continuously included in the cohort after September 1, 2014, and followed through December 31, 2017. Participants were censored if they died, changed enrollment status, or developed a study outcome. Most of the analyses were conducted from 2018 to 2019, and additional analyses were performed from 2021 to 2022. EXPOSURES: Use of PCV13 vaccination 14 days or more before pneumonia hospitalization. MAIN OUTCOMES AND MEASURES: Discrete-time survival models were used to estimate the incidence rate ratio (IRR) and number of pneumonia hospitalizations averted through PCV13 use. The adjusted IRR for the association of PCV13 vaccination with pneumonia hospitalization was used to estimate vaccine effectiveness (VE). RESULTS: At the end of follow-up (December 2017), 24121625 beneficiaries (13593975 women [56.4%]; 418005 [1.7%] Asian, 1750807 [4.8%] Black, 338044 [1.4%] Hispanic, 111508 [0.5%] Native American, and 20700948 [85.8%] White individuals) were in the cohort; 4936185 (20.5%) had received PCV13 only, and 10646220 (79.5%) had not received any pneumococcal vaccines. More than half of the beneficiaries in the cohort were younger than 75 years, White, and had either immunocompromising or chronic medical conditions. Coverage with PCV13 increased from 0.8% (September 2014) to 41.5% (December 2017). The VE for PCV13 was estimated at 6.7% (95% CI, 5.9%-7.5%) for pneumonia, 4.7% (95% CI, 3.9%-5.6%) for non-HA pneumonia, and 5.8% (95% CI, 2.6%-8.9%) for LP. From September 2014 through December 2017, an estimated 35127 pneumonia (95% CI, 33011-37270), 24643 non-HA pneumonia (95% CI, 22761-26552), and 1294 LP (95% CI, 797-1819) hospitalizations were averted through PCV13 use. CONCLUSIONS AND RELEVANCE: The study results suggest that PCV13 use was associated with reduced pneumonia hospitalization among Medicare beneficiaries 65 years or older, many of whom had underlying medical conditions. Increased PCV13 coverage and use of recently approved higher-valent pneumococcal conjugate vaccines may avert additional pneumonia hospitalizations in adults.

OBJECTIVE: To determine the difference in rate of weight gain from birth to 5 years based on exposure to maternal group B streptococcal (GBS) intrapartum antibiotic prophylaxis (IAP). DESIGN: Retrospective cohort study of 13 804 infants. SETTING: Two perinatal centres and a primary paediatric care network in Philadelphia. PARTICIPANTS: Term infants born 2007-2012, followed longitudinally from birth to 5 years of age. EXPOSURES: GBS IAP defined as penicillin, ampicillin, cefazolin, clindamycin or vancomycin administered ≥4 hours prior to delivery to the mother. Reference infants were defined as born to mothers without (vaginal delivery) or with other (caesarean delivery) intrapartum antibiotic exposure. OUTCOMES: Difference in rate of weight change from birth to 5 years was assessed using longitudinal rate regression. Analysis was a priori stratified by delivery mode and adjusted for relevant covariates. RESULTS: GBS IAP was administered to mothers of 2444/13 804 (17.7%) children. GBS IAP-exposed children had a significantly elevated rate of weight gain in the first 5 years among vaginally-born (adjusted rate difference 1.44% (95% CI 0.3% to 2.6%)) and caesarean-born (3.52% (95% CI 1.9% to 5.2%)) children. At 5 years, the rate differences equated to an additional 0.24 kg among vaginally-born children and 0.60 kg among caesarean-born children. CONCLUSION: GBS-specific IAP was associated with a modest increase in rate of early childhood weight gain. GBS IAP is an effective intervention to prevent perinatal GBS disease-associated morbidity and mortality. However, these findings highlight the need to better understand effects of intrapartum antibiotic exposure on childhood growth and support efforts to develop alternate prevention strategies.

BACKGROUND: Intrapartum antibiotic prophylaxis (IAP) reduce a newborn's risk of group B streptococcal infection (GBS) but may lead to an increased childhood body mass index (BMI). METHODS: Retrospective cohort study of infants (n=223,431) born 2007-2015 in an integrated healthcare system. For vaginal delivery, we compared children exposed to GBS-IAP and to any other type or duration of intrapartum antibiotics to no antibiotic exposure. For Cesarean delivery, we compared children exposed to GBS-IAP to those exposed to all other intrapartum antibiotics, including surgical prophylaxis. BMI over 5 years was compared using non-linear multivariate models with B-spline functions, stratified by delivery mode and adjusted for demographics, maternal factors, breastfeeding and childhood antibiotic exposure. RESULTS: In vaginal deliveries, GBS-IAP was associated with higher BMI from 0.5 to 5.0 years of age compared to no antibiotics (P<0.0001 for all time points, Δ BMI at age 5 years 0.12 kg/m 2, 95% CI 0.07 to 0.16 kg/m 2). Other antibiotics were associated with higher BMI from 0.3 to 5.0 years of age. In Cesarean deliveries, GBS-IAP was associated with increased BMI from 0.7 years to 5.0 years of age (P<0.05 for 0.7-0.8 years, P<0.0001 for all other time points) compared to other antibiotics (Δ BMI at age 5 years 0.24 kg/m 2, 95% CI 0.14 to 0.34 kg/m 2). Breastfeeding did not modify these associations. CONCLUSION: GBS-IAP was associated with a small but sustained increase in BMI starting at very early age. This association highlights the need to better understand the effects of perinatal antibiotic exposure on childhood health.

BACKGROUND: Reported outbreaks of invasive group A Streptococcus (iGAS) infections among people who inject drugs (PWID) and people experiencing homelessness (PEH) have increased, concurrent with rising US iGAS rates. We describe epidemiology among iGAS patients with these risk factors. METHODS: We analyzed iGAS infections from population-based Active Bacterial Core surveillance (ABCs) at 10 US sites from 2010 to 2017. Cases were defined as GAS isolated from a normally sterile site or from a wound in patients with necrotizing fasciitis or streptococcal toxic shock syndrome. GAS isolates were emm typed. We categorized iGAS patients into four categories: injection drug use (IDU) only, homelessness only, both, and neither. We calculated annual change in prevalence of these risk factors using log binomial regression models. We estimated national iGAS infection rates among PWID and PEH. RESULTS: We identified 12 386 iGAS cases; IDU, homelessness, or both were documented in ~13%. Skin infections and acute skin breakdown were common among iGAS patients with documented IDU or homelessness. Endocarditis was 10-fold more frequent among iGAS patients with documented IDU only versus those with neither risk factor. Average percentage yearly increase in prevalence of IDU and homelessness among iGAS patients was 17.5% and 20.0%, respectively. iGAS infection rates among people with documented IDU or homelessness were ~14-fold and 17- to 80-fold higher, respectively, than among people without those risks. CONCLUSIONS: IDU and homelessness likely contribute to increases in US incidence of iGAS infections. Improving management of skin breakdown and early recognition of skin infection could prevent iGAS infections in these patients.

BACKGROUND: In the first 2 years after a nationwide mass vaccination campaign of 1-29-year-olds with a meningococcal serogroup A conjugate vaccine (MenAfriVac) in Burkina Faso, carriage and disease due to serogroup A Neisseria meningitidis were nearly eliminated. We aimed to assess the long-term effect of MenAfriVac vaccination on meningococcal carriage and herd immunity. METHODS: We did four cross-sectional studies of meningococcal carriage in people aged 9 months to 36 years in two districts of Burkina Faso between May 2, 2016, and Nov 6, 2017. Demographic information and oropharyngeal swabs were collected. Meningococcal isolates were characterised using whole-genome sequencing. FINDINGS: Of 14 295 eligible people, 13 758 consented and had specimens collected and laboratory results available, 1035 of whom were meningococcal carriers. Accounting for the complex survey design, prevalence of meningococcal carriage was 7.60% (95% CI 5.67-9.52), including 6.98% (4.86-9.11) non-groupable, 0.48% (0.01-0.95) serogroup W, 0.10% (0.01-0.18) serogroup C, 0.03% (0.00-0.80) serogroup E, and 0% serogroup A. Prevalence ranged from 5.44% (95% CI 4.18-6.69) to 9.14% (6.01-12.27) by district, from 4.67% (2.71-6.64) to 11.17% (6.75-15.59) by round, and from 3.39% (0.00-8.30) to 10.43% (8.08-12.79) by age group. By clonal complex, 822 (88%) of 934 non-groupable isolates were CC192, all 83 (100%) serogroup W isolates were CC11, and nine (69%) of 13 serogroup C isolates were CC10217. INTERPRETATION: Our results show the continued effect of MenAfriVac on serogroup A meningococcal carriage, for at least 7 years, among vaccinated and unvaccinated cohorts. Carriage prevalence of epidemic-prone serogroup C CC10217 and serogroup W CC11 was low. Continued monitoring of N meningitidis carriage will be crucial to further assess the effect of MenAfriVac and inform the vaccination strategy for future multivalent meningococcal vaccines. FUNDING: Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.

Respondent-Driven Sampling (RDS) is a network-based method for sampling hard-to-reach populations that is widely used by public health agencies and researchers worldwide. Estimation of population characteristics from RDS data is challenging due to the unobserved population network, and multiple point and variance estimators have been proposed. Research evaluating these estimators has been limited and largely focused on point estimation; this analysis is the first evaluation of multiple variance estimators currently in use. We evaluated the performance of RDS variance estimators via simulations of RDS on synthetic networked populations constructed from 40 RDS surveys of injection drug users in the United States. In these simulations, average design effects (DEs) were lower and average 95% confidence interval (CI) coverage percentages were higher than suggested in previous work: typical DE range=1-3; average 95% CI coverage=93%. However, DE and CI coverage vary across the 40 sets of simulations, suggesting that the characteristics of a given study should be evaluated to assess estimator performance. We also found that simulation results are sensitive to whether sampling is conducted with replacement and the approach used to create CIs. We conclude that CI coverage rates and DEs are often acceptable but not perfect and that RDS estimates are usually reliable in scenarios where RDS assumptions are met. While RDS estimation performed reasonably well, we found strong evidence that the simple random sample variance estimator and corresponding CIs significantly underestimate variance and should not be used to analyze RDS data. © The Author 2017. Published by Oxford University Press on behalf of the American Association for Public Opinion Research. All rights reserved.

In the United States, 9% of human immunodeficiency virus (HIV) infections diagnosed in 2015 were attributed to injection drug use (1). In 2015, 79% of diagnoses of HIV infection among persons who inject drugs occurred in urban areas (2). To monitor the prevalence of HIV infection and associated behaviors among persons who inject drugs, CDC's National HIV Behavioral Surveillance (NHBS) conducts interviews and HIV testing in selected metropolitan statistical areas (MSAs) (3). The prevalence of HIV infection among persons who inject drugs in 20 MSAs in 2015 was 7%. In a behavioral analysis of HIV-negative persons who inject drugs, an estimated 27% receptively shared syringes and 67% had condomless vaginal sex in the previous 12 months. During the same period, 58% had tested for HIV infection and 52% received syringes from a syringe services program. Given the increased number of persons newly injecting drugs who are at risk for HIV infection because of the recent opioid epidemic (2,4), these findings underscore the importance of continuing and expanding health services, HIV prevention programs, and community-based strategies, such as those provided by syringe services programs, for this population.

BACKGROUND: Monitoring the effects of HIV prevention efforts on risk behaviors among persons who inject drugs is a key to inform prevention programs and policy. METHODS: Using data from the 2012 National HIV Behavioral Surveillance interviews with persons who inject drugs across 20 US cities (n = 10,171), we conducted latent class analysis to identify injection risk classes and assess the relationship between engagement in prevention services and injection-related risk behavior. We conducted stratified analyses to examine the consistency of these associations across different geographical regions. RESULTS: The latent class analysis identified 6 distinct classes of injection-related risk behavior. The class structure was consistent across regions of the United States, but the distribution of risk classes varied significantly across regions. With covariate adjustment, the South had the most high-risk behavior (21%) and the Midwest had the least (6%). Participation in syringe access services and other prevention services was the lowest in the South. Syringe access was associated with a significantly lower likelihood of membership in the highest risk class in all regions except the Midwest. Participation in individual or group intervention with a practical skills component was associated with less risky injection behavior in all regions except the Northeast. Interventions that featured only safer injection information and discussion had no relationship with risk class. CONCLUSIONS: Our findings support evidence of the effectiveness of syringe service programs and safer injection skills training in reducing high-risk injection behavior and underscore the need to improve access to these prevention interventions in the South of the United States.

In January 2015, an outbreak of undiagnosed human immunodeficiency virus (HIV) infections among persons who inject drugs (PWID) was recognized in rural Indiana. By September 2016, 205 persons in this community of approximately 4400 had received a diagnosis of HIV infection. We report results of new approaches to analyzing epidemiologic and laboratory data to understand transmission during this outbreak. HIV genetic distances were calculated using the polymerase region. Networks were generated using data about reported high-risk contacts, viral genetic similarity, and their most parsimonious combinations. Sample collection dates and recency assay results were used to infer dates of infection. Epidemiologic and laboratory data each generated large and dense networks. Integration of these data revealed subgroups with epidemiologic and genetic commonalities, one of which appeared to contain the earliest infections. Predicted infection dates suggest that transmission began in 2011, underwent explosive growth in mid-2014, and slowed after the declaration of a public health emergency. Results from this phylodynamic analysis suggest that the majority of infections had likely already occurred when the investigation began and that early transmission may have been associated with sexual activity and injection drug use. Early and sustained efforts are needed to detect infections and prevent or interrupt rapid transmission within networks of uninfected PWID.

Background In January 2015, a total of 11 new diagnoses of human immunodeficiency virus (HIV) infection were reported in a small community in Indiana. We investigated the extent and cause of the outbreak and implemented control measures. Methods We identified an outbreak-related case as laboratory-confirmed HIV infection newly diagnosed after October 1, 2014, in a person who either resided in Scott County, Indiana, or was named by another case patient as a syringe-sharing or sexual partner. HIV polymerase (pol) sequences from case patients were phylogenetically analyzed, and potential risk factors associated with HIV infection were ascertained. Results From November 18, 2014, to November 1, 2015, HIV infection was diagnosed in 181 case patients. Most of these patients (87.8%) reported having injected the extended-release formulation of the prescription opioid oxymorphone, and 92.3% were coinfected with hepatitis C virus. Among 159 case patients who had an HIV type 1 pol gene sequence, 157 (98.7%) had sequences that were highly related, as determined by phylogenetic analyses. Contact tracing investigations led to the identification of 536 persons who were named as contacts of case patients; 468 of these contacts (87.3%) were located, assessed for risk, tested for HIV, and, if infected, linked to care. The number of times a contact was named as a syringe-sharing partner by a case patient was significantly associated with the risk of HIV infection (adjusted risk ratio for each time named, 1.9; P<0.001). In response to this outbreak, a public health emergency was declared on March 26, 2015, and a syringe-service program in Indiana was established for the first time. Conclusions Injection-drug use of extended-release oxymorphone within a network of persons who inject drugs in Indiana led to the introduction and rapid transmission of HIV. (Funded by the state government of Indiana and others.).

INTRODUCTION: Persons who inject drugs (PWID) continue to be disproportionately affected by HIV. HIV testing is key to reducing HIV transmission by increasing awareness of HIV status and linking HIV-positive persons to care. Using data from PWID participating in CDC's National HIV Behavioral Surveillance (NHBS) system, we examined prevalence of recent HIV testing among PWID by certain characteristics to guide interventions to increase HIV testing. METHODS: We analyzed NHBS data from PWID 18 years or older recruited via respondent-driven sampling in 20 US cities in 2012. We examined demographic and behavioral factors associated with recent HIV testing (within 12 months before interview) using a Poisson model to calculate adjusted prevalence ratios (aPRs). RESULTS: Of 9555 PWID, 53% had recently tested for HIV. In multivariable analysis, HIV testing was more frequent among participants who visited a healthcare provider (aPR 1.50, P<0.001), participated in alcohol or drug treatment (aPR 1.21, P<0.001), or received an HIV prevention intervention (aPR 1.26, P<0.001). HIV testing was also more frequent among participants who received free sterile syringes (aPR 1.12, P<0.001). DISCUSSION: Only half of PWID participating in NHBS in 2012 reported recent HIV testing. HIV testing was more frequent among participants who accessed health and HIV prevention services. To increase HIV testing among PWID, it is important for providers in healthcare and HIV prevention settings to proactively assess risk factors for HIV, including injection drug use, and offer a wide range of appropriate interventions, such as HIV testing.

BACKGROUND: Annual human immunodeficiency virus (HIV) testing is considered a key strategy for HIV prevention for men who have sex with men (MSM). In Puerto Rico, HIV research has primarily focused on injection drug use, yet male-to-male sexual transmission has been increasing in recent years. METHODS: Cross-sectional data from the National HIV Behavioral Surveillance system collected in 2011 in San Juan, Puerto Rico, were analyzed to identify factors associated with HIV testing in the past 12 months (recent testing). RESULTS: Overall, 50% of participants were tested recently. In the multivariate analysis, testing recently was associated with having multiple partners in the past 12 months (adjusted prevalence ratio [aPR] [≥4 vs 1 partner] = 1.5; 95% confidence interval [95% CI], 1.2–2.0), visiting a health care provider in the past 12 months (aPR, 1.4; 95% CI, 1.04–1.8), and disclosing male-male attraction/sex to a health care provider (aPR< 1.4; 95% CI, 1.1–1.7). CONCLUSIONS: Human immunodeficiency virus testing was suboptimal among MSM in San Juan. Strategies to increase HIV testing among MSM may include promoting HIV testing for all sexually active MSM including those with fewer partners, increasing utilization of the healthcare system, and improving patient-provider communication.

OBJECTIVES: Respondent-driven sampling (RDS) is a new data collection methodology used to estimate characteristics of hard-to-reach groups, such as the HIV prevalence in drug users. Many national public health systems and international organizations rely on RDS data. However, RDS reporting quality and available reporting guidelines are inadequate. We carried out a systematic review of RDS studies and present Strengthening the Reporting of Observational Studies in Epidemiology for RDS Studies (STROBE-RDS), a checklist of essential items to present in RDS publications, justified by an explanation and elaboration document. STUDY DESIGN AND SETTING: We searched the MEDLINE (1970-2013), EMBASE (1974-2013), and Global Health (1910-2013) databases to assess the number and geographical distribution of published RDS studies. STROBE-RDS was developed based on STROBE guidelines, following Guidance for Developers of Health Research Reporting Guidelines. RESULTS: RDS has been used in over 460 studies from 69 countries, including the USA (151 studies), China (70), and India (32). STROBE-RDS includes modifications to 12 of the 22 items on the STROBE checklist. The two key areas that required modification concerned the selection of participants and statistical analysis of the sample. CONCLUSION: STROBE-RDS seeks to enhance the transparency and utility of research using RDS. If widely adopted, STROBE-RDS should improve global infectious diseases public health decision making.

In the United States, an estimated 7% of new diagnoses of human immunodeficiency virus (HIV) infection in 2012 were attributed to injection drug use, and an additional 3% to male-to-male sexual contact and injection drug use. To monitor HIV prevalence and behaviors associated with HIV risk and prevention among persons who inject drugs (PWID), CDC's National HIV Behavioral Surveillance (NHBS) system conducts interviews and HIV testing in selected cities. This report summarizes HIV prevalence and behaviors among PWID interviewed and tested in 20 cities in 2012. Of the 10,002 PWID tested, 11% had a positive HIV test result. Among 9,425 PWID included in the behavioral analysis, 30% receptively shared syringes, 70% had vaginal sex without a condom, 25% had heterosexual anal sex without a condom, and 5% of males had male-to-male sexual contact without a condom in the previous 12 months. Fifty-one percent of PWID included in the behavioral analysis had been tested for HIV, 25% participated in an HIV behavioral intervention, and 39% participated in substance abuse treatment in the previous 12 months. Additional efforts are needed to reduce risk behaviors and increase access to HIV testing, drug treatment, and other HIV prevention programs to further reduce HIV infections among PWID.