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Recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may pose a threat to immunity. A systematic landscape of neutralizing antibodies against emerging variants is needed. We systematically searched for studies that evaluated neutralizing antibody titers induced by previous infection or vaccination against SARS-CoV-2 variants and collected individual data. We identified 106 studies meeting the eligibility criteria. Lineage B.1.351 (beta), P.1 (gamma) and B.1.617.2 (delta) significantly escaped natural infection–mediated neutralization, with an average of 4.1-fold (95% confidence interval [CI]: 3.6–4.7-fold), 1.8-fold (1.4–2.4-fold), and 3.2-fold (2.4–4.1-fold) reduction in live virus neutralization assay, while neutralizing titers against B.1.1.7 (alpha) decreased slightly (1.4-fold [95% CI: 1.2–1.6-fold]). Serum from vaccinees also led to significant reductions in neutralization of B.1.351 across different platforms, with an average of 7.1-fold (95% CI: 5.5–9.0-fold) for nonreplicating vector platform, 4.1-fold (3.7–4.4-fold) for messenger RNA platform, and 2.5-fold (1.7–2.9-fold) for protein subunit platform. Neutralizing antibody levels induced by messenger RNA vaccines against SARS-CoV-2 variants were similar to, or higher, than that derived from naturally infected individuals. [ABSTRACT FROM AUTHOR]

Background Serological assays detecting anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies are being widely deployed in studies and clinical practice. However, the duration and effectiveness of the protection conferred by the immune response remains to be assessed in population-based samples. To estimate the incidence of newly acquired SARS-CoV-2 infections in seropositive individuals as compared to seronegative controls, we conducted a retrospective longitudinal matched study. Methods A seroprevalence survey including a representative sample of the population was conducted in Geneva, Switzerland, between April and June 2020, immediately after the first pandemic wave. Seropositive participants were matched one-to-two to seronegative controls, using a propensity-score including age, gender, immunodeficiency, body mass index (BMI), smoking status, and education level. Each individual was linked to a state-registry of SARS-CoV-2 infections. Our primary outcome was confirmed infections occurring from serological status assessment to the end of the second pandemic wave (January 2021). Results Among 8344 serosurvey participants, 498 seropositive individuals were selected and matched with 996 seronegative controls. After a mean follow-up of 35.6 (standard deviation [SD] 3.2) weeks, 7 out of 498 (1.4%) seropositive subjects had a positive SARS-CoV-2 test, of whom 5 (1.0%) were classified as reinfections. In contrast, the infection rate was higher in seronegative individuals (15.5%, 154/996) during a similar follow-up period (mean 34.7 [SD 3.2] weeks), corresponding to a 94% (95% confidence interval [CI]: 86%– 98%, P  < .001) reduction in the hazard of having a positive SARS-CoV-2 test for seropositives. Conclusions Seroconversion after SARS-CoV-2 infection confers protection against reinfection lasting at least 8 months. These findings could help global health authorities establishing priority for vaccine allocation. [ABSTRACT FROM AUTHOR]

Background Despite advances in prevention, detection, and treatment, cholera remains a major public health problem in Bangladesh and little is known about cholera outside of limited historical sentinel surveillance sites. In Bangladesh, a comprehensive national cholera control plan is essential, although national data are needed to better understand the magnitude and geographic distribution of cholera. Methods We conducted systematic hospital-based cholera surveillance among diarrhea patients in 22 sites throughout Bangladesh from 2014 to 2018. Stool specimens were collected and tested for Vibrio cholerae by microbiological culture. Participants' socioeconomic status and clinical, sanitation, and food history were recorded. We used generalized estimating equations to identify the factors associated with cholera among diarrhea patients. Results Among 26 221 diarrhea patients enrolled, 6.2% (n = 1604) cases were V. cholerae O1. The proportion of diarrhea patients positive for cholera in children <5 years was 2.1% and in patients ≥5 years was 9.5%. The proportion of cholera in Dhaka and Chittagong Division was consistently high. We observed biannual seasonal peaks (pre- and postmonsoon) for cholera across the country, with higher cholera positivity during the postmonsoon in western regions and during the pre–monsoon season in eastern regions. Cholera risk increased with age, occupation, and recent history of diarrhea among household members. Conclusions Cholera occurs throughout a large part of Bangladesh. Cholera-prone areas should be prioritized to control the disease by implementation of targeted interventions. These findings can help strengthen the cholera-control program and serve as the basis for future studies for tracking the impact of cholera-control interventions in Bangladesh. [ABSTRACT FROM AUTHOR]

Background Diphtheria, once a major cause of childhood morbidity and mortality, all but disappeared following introduction of diphtheria vaccine. Recent outbreaks highlight the risk diphtheria poses when civil unrest interrupts vaccination and healthcare access. Lack of interest over the last century resulted in knowledge gaps about diphtheria's epidemiology, transmission, and control. Methods We conducted 9 distinct systematic reviews on PubMed and Scopus (March–May 2018). We pooled and analyzed extracted data to fill in these key knowledge gaps. Results We identified 6934 articles, reviewed 781 full texts, and included 266. From this, we estimate that the median incubation period is 1.4 days. On average, untreated cases are colonized for 18.5 days (95% credible interval [CrI], 17.7–19.4 days), and 95% clear Corynebacterium diphtheriae within 48 days (95% CrI, 46–51 days). Asymptomatic carriers cause 76% (95% confidence interval, 59%–87%) fewer cases over the course of infection than symptomatic cases. The basic reproductive number is 1.7–4.3. Receipt of 3 doses of diphtheria toxoid vaccine is 87% (95% CrI, 68%–97%) effective against symptomatic disease and reduces transmission by 60% (95% CrI, 51%–68%). Vaccinated individuals can become colonized and transmit; consequently, vaccination alone can only interrupt transmission in 28% of outbreak settings, making isolation and antibiotics essential. While antibiotics reduce the duration of infection, they must be paired with diphtheria antitoxin to limit morbidity. Conclusions Appropriate tools to confront diphtheria exist; however, accurate understanding of the unique characteristics is crucial and lifesaving treatments must be made widely available. This comprehensive update provides clinical and public health guidance for diphtheria-specific preparedness and response. [ABSTRACT FROM AUTHOR]