Understanding vaccine-mediated protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is critical to overcoming the global coronavirus disease 2019 (COVID-19) pandemic. We investigate mRNA-vaccine-induced antibody responses against the reference strain, seven variants, and seasonal coronaviruses in 168 healthy individuals at three time points: before vaccination, after the first dose, and after the second dose. Following complete vaccination, both naive and previously infected individuals developed comparably robust SARS-CoV-2 spike antibodies and variable levels of cross-reactive antibodies to seasonal coronaviruses. However, the strength and frequency of SARS-CoV-2 neutralizing antibodies in naive individuals were lower than in previously infected individuals. After the first vaccine dose, one-third of previously infected individuals lacked neutralizing antibodies; this was improved to one-fifth after the second dose. In all individuals, neutralizing antibody responses against the Alpha and Delta variants were weaker than against the reference strain. Our findings support future tailored vaccination strategies against emerging SARS-CoV-2 variants as mRNA-vaccine-induced neutralizing antibodies are highly variable among individuals.

Background: Social marketing interventions are important in developing nations. Both increasing use and shifting users from receiving subsidised condoms need to be pursued using a Total Market Approach (TMA). This paper reviews the performance of social marketing through a cross-country comparison of condom use, equity and market share, plus a case study illustrating how TMA can be applied. Methods: Demographic and Health Survey data (1998–2007) provide condom use trends, concentration indices and sources of supply by gender for 11 African countries. Service delivery information and market research provide market share data for the same period. For the case study, two-yearly surveys (2001–09) are the source of condom trends, and retail audit data (2007–09) provide sustainability data. Results: Among women, condom use with a non-marital, non-cohabiting partner increased significantly in 7 of 11 countries. For men, 5 of 11 countries showed an increase in condom use. Equity improved for men in five countries and was achieved in two; for women, equity improved in three. Most obtained condoms from shops and pharmacies; social marketing was the dominant source of supply. Data from Kenya were informative for TMA, showing improvements in condom use over time, but sustainability results were mixed and equity was not measured. Overall market value and number of brands increased; however, subsidies increased over time. Conclusions: Condom social marketing interventions have advanced and achieved the goals of improving use and making condoms available in the private sector. It is time to manage interventions and influence markets to improve equity and sustainability.

Background: Sapovirus is increasingly recognized as an important cause of acute gastroenteritis (AGE) in children. We identified risk factors and characterized the clinical profile of sapovirus AGE in a birth cohort in León, Nicaragua. Methods: We conducted a case-control study nested within a birth cohort (n = 444). Fieldworkers conducted weekly household AGE surveillance. AGE stools were tested for sapovirus by reverse transcriptase quantitative polymerase chain reaction. For each first sapovirus episode, we selected 2 healthy age-matched controls and estimated independent risk factors of sapovirus AGE using conditional logistic regression. We compared clinical characteristics of sapovirus AGE episodes with episodes associated with other etiologies and identified co-infections with other enteric pathogens. Results: From June 2017 to July 2019, we identified 63 first sapovirus AGE episodes and selected 126 controls. Having contact with an individual with AGE symptoms and vaginal delivery were independent risk factors for sapovirus AGE. All cases experienced diarrhea, lasting a median 6 days; 23% experienced vomiting. Compared with children with AGE due to another etiology, sapovirus AGE was similar in severity, with less reported fever. Most cases experienced co-infections and were more likely than controls to be infected with diarrheagenic Escherichia coli or astrovirus. Conclusions: Sapovirus was a commonly identified AGE etiology in this Central American setting, and symptoms were similar to AGE associated with other etiologies. The association between vaginal delivery and sapovirus is a novel finding. Gut microbiome composition might mediate this relationship, or vaginal delivery might be a proxy for other risk factors. Further investigation into more specific biological mechanisms is warranted.

Background Little is known about risk factors for persistent high-risk human papillomavirus (hrHPV) infection in low-income settings, and prior research has not quantified the relative duration of hrHPV infections stratified by risk factors. We compared the duration of hrHPV infection among female sex workers (FSWs) by exposure to sexually transmitted infections (STIs), using a highly sensitive biomarker assay. Methods From 2009 to 2011, 350 FSWs enrolled in this longitudinal study. Every 3 months, sociodemographic and sexual behavior data were collected via questionnaire, and APTIMA assays were used to detect the rRNA of Chlamydia trachomatis (CT), Neisseria gonorrhea, Trichomonas vaginalis, Mycoplasma genitalium, and messenger RNA of the E6/E7 oncoproteins expressed by hrHPV. Among 173 FSW who were infected with hrHPV during the observation period, accelerated failure time models estimated time ratios (TRs) for duration of hrHPV infection, comparing FSW infected with STIs at baseline to STI-uninfected FSWs. Results Median follow-up time was 26.2 months (interquartile range, 18.8–27.5 months). The median duration of hrHPV infection among all FSWs was 9.3 months (95% confidence interval [CI], 9.3–11.5). The duration of hrHPV infection among FSW infected with CT at baseline was greater than that among FSWs who were uninfected (adjusted TR, 1.7; 95% CI, 1.2–2.6). Among FSWs who were coinfected with hrHPV and CT at baseline, the adjusted TR was 3.4 (95% CI, 2.5–5.4) compared with FSWs infected with hrHPV only. No other STI was associated with hrHPV duration. Conclusions Recent or concurrent CT infection was associated with prolonged hrHPV infection among a cohort of Nairobi FSWs. Management of CT could reduce risk for hrHPV persistence.

Implementing organizations are pressured to be accountable for performance. Many health impact metrics present limitations for priority setting; they do not permit comparisons across different interventions or health areas. In response, Population Services International (PSI) adopted the disability-adjusted life year (DALY) averted as its bottom-line performance metric. While international standards exist for calculating DALYs to determine burden of disease (BOD), PSI's use of DALYs averted is novel. It uses DALYs averted to assess and compare the health impact of its country programs, and to understand the effectiveness of a portfolio of interventions. This paper describes how the adoption of DALYs averted influenced organizational strategy and presents the advantages and constraints of using the metric.