Background: Asymptomatic SARS-CoV-2 infections have raised concerns for public health policies to manage epidemics. This systematic review and meta-analysis aimed to estimate the age-specific proportion of asymptomatic SARS-CoV-2 infected persons globally by year of age. Methods: We searched PubMed, Embase, medRxiv and Google Scholar on September 10, 2020, and March 1, 2021. We included studies conducted during January to December 2020, before routine vaccination against COVID-19. Because we expected the relationship between the asymptomatic proportion and age to be nonlinear, multilevel mixed-effects logistic regression (QR decomposition) with a restricted cubic spline was used to model asymptomatic proportions as a function of age. Results: A total of 38 studies were included in the meta-analysis. In total, 6556 of 14,850 cases were reported as asymptomatic. The overall estimate of the proportion of people who became infected with SARS-CoV-2 and remained asymptomatic throughout infection was 44.1% (6556/14,850, 95% CI: 43.3%–45.0%). The predicted asymptomatic proportion peaked in children (36.2%, 95% CI: 26.0%–46.5%) at 13.5 years, gradually decreased by age and was lowest at 90.5 years of age (8.1%, 95% CI: 3.4%–12.7%). Conclusions: Given the high rates of asymptomatic carriage in adolescents and young adults and their active role in virus transmission in the community, heightened vigilance and public health strategies are needed among these individuals to prevent disease transmission.

Real-world data on the effectiveness of COVID-19 vaccines against the Omicron variant (B.1.1.529) is limited. This systematic review aimed to investigate the real-world effectiveness and durability of protection conferred by primary course and booster vaccines against confirmed Omicron infection, and severe outcomes. We systematically searched literature up to 1 August 2022. Meta-analysis was performed with the DerSimonian-Laird random-effects model to estimate the pooled vaccine effectiveness (VE). Overall, 28 studies were included representing 11 million individuals. The pooled VE against Omicron infection was 20.4% (95%CI: 12.1–28.7%) and 23.4% (95%CI: 13.5–33.3%) against symptomatic infection with variation based on vaccine type and age groups. VE sharply declined from 28.1% (95%CI: 19.1–37.1%) at three months to 3.9% (95%CI: −24.8–32.7%) at six months. Similar trends were observed for symptomatic Omicron infection. A booster dose restored protection against Omicron infection up to 51.1% (95%CI: 43.8–58.3%) and 57.3% (95%CI: 54.0–60.5%) against symptomatic infection within three months; however, this waned to 32.8% (95%CI: 16.8–48.7%) within six months. VE against severe Omicron infection following the primary course was 63.6% (95%CI: 57.5–69.7%) at three months, decreased to 49% (95%CI: 35.7–63.4%) within six months, and increased to 86% after the first or second booster dose.

Neisseria gonorrhoeae infection (gonorrhoea) is a global public health challenge, causing substantial sexual and reproductive health consequences, such as infertility, pregnancy complications and increased acquisition or transmission of HIV. There is an urgency to controlling gonorrhoea because of increasing antimicrobial resistance to ceftriaxone, the last remaining treatment option, and the potential for gonorrhoea to become untreatable. No licensed gonococcal vaccine is available. Mounting observational evidence suggests that N. meningitidis serogroup B outer membrane vesicle-based vaccines may induce cross-protection against N. gonorrhoeae (estimated 30%-40% effectiveness using the 4CMenB vaccine). Clinical trials to determine the efficacy of the 4CMenB vaccine against N. gonorrhoeae are underway, as are Phase 1/2 studies of a new gonococcal-specific vaccine candidate. Ultimately, a gonococcal vaccine must be accessible, affordable and equitably dispensed, given that those most affected by gonorrhoea are also those who may be most disadvantaged in our societies, and most cases are in less-resourced settings. This vaccine value profile (VVP) provides a high level, holistic assessment of the current data to inform the potential public health, economic and societal value of pipeline vaccines. This was developed by a working group of subject matter experts from academia, non-profit organizations, public private partnerships and multi-lateral organizations. All contributors have extensive expertise on various elements of the N. gonorrhoeae VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using published data obtained from peer-reviewed journals or reports.

Of 109 children admitted to a tertiary paediatric hospital with a diagnosis of invasive meningococcal disease from 2000–2011, 37.6% (n = 41) developed sequelae; for serogroup B, 41.3% developed sequelae. Independent predictors of sequelae included: fever ≥ 39°C on hospital presentation [odds ratio (OR): 4.5; P = 0.012] and a diagnosis of septicemia with meningitis compared with septicemia alone (OR: 15.5; P < 0.001) and meningitis alone (OR: 7.8; P = 0.002).