Throughout 2020, COVID-19 interventions prioritised symptomatic individuals despite growing evidence of pre-symptomatic and asymptomatic transmission. From the pandemic we have learned that global health is slow to quantify asymptomatic disease transmission and slow to implement relevant interventions. While asymptomatic infectious periods exist for nearly all pathogens, it is frequently ignored during case finding, and there are limited research efforts to understand its potential to drive small scale outbreaks, epidemics and pandemics.

The impact of COVID-19 disruptions on global Bacillus Calmette-Guérin (BCG) coverage and paediatric tuberculosis (TB) mortality is still unknown. To fill this evidence-gap and guide mitigation measures, we estimated the impact of COVID-19 disruptions on global BCG coverage and paediatric TB mortality. First, we used data from multiple sources to estimate COVID-19-disrupted BCG vaccination coverage. Second, using a static mathematical model, we estimated the number of additional paediatric TB deaths in the first 15 years of life due to delayed/missed vaccinations in 14 scenarios—varying in duration of disruption, and magnitude and timing of catch-up. We estimated a 25% reduction in global BCG coverage within the disruption period. The best-case scenario (3-month disruption, 100% catch-up within 3 months) resulted in an additional 886 (0.5%) paediatric TB deaths, and the worst-case scenario (6-month disruption with no catch-up) resulted in an additional 33,074 (17%) deaths. The magnitude of catch-up was found to be the most influential variable in minimising excess paediatric TB mortality. Our results show that ensuring catch-up vaccination of missed children is a critical priority, and delivery of BCG alongside other routine vaccines may be a feasible way to achieve catch-up. Urgent action is required to support countries with recovering vaccination coverages to minimise paediatric deaths.

Background: Individuals with bacteriologically confirmed pulmonary tuberculosis disease (TB) that do not report symptoms (subclinical TB) represent around half of all prevalent cases of TB, yet their contribution to Mycobacterium tuberculosis ( Mtb ) transmission is unknown, especially compared to individuals who report symptoms at time of diagnosis (clinical TB). Relative infectiousness can be approximated by cumulative infections in household contacts, but such data are rare. Methods and Findings: We reviewed the literature to identify studies where surveys of Mtb infection were linked to population surveys of TB disease. We collated individual population data for analysis and used literature on the relative durations of subclinical and clinical TB to estimate relative infectiousness through a cumulative hazard model, accounting for sputum-smear status. Relative prevalence of subclinical and clinical disease in high burden settings was used to estimate the contribution of subclinical TB to global Mtb transmission. We collated data on 414 index cases and 789 household contacts from three prevalence surveys (Bangladesh, Philippines, Viet Nam) and one case-finding trial in Viet Nam. The odds ratio of household infection prevalence was 1.2 (0.6-2.3, 95% Confidence Interval). Adjusting for duration of disease, we found a per-unit-time infectiousness of subclinical TB relative to clinical TB of 1.93 (0.62-6.18, 95% Prediction Interval (PrI)). 14 countries across Asia and Africa provided data on relative prevalence of subclinical and clinical TB, suggesting an estimated 68% (27-92%, 95% PrI) of global transmission is from subclinical TB. Conclusions: Our results suggest that subclinical TB contributes substantially to transmission and needs to be diagnosed and treated for effective progress towards TB elimination.

To estimate the hospitalization and mortality impact of influenza, respiratory syncytial virus (RSV), human metapneumovirus (HMPV), rhino/enteroviruses (RV/EV), and SARS-CoV-2. We applied age-specific time series regression models to weekly vital statistics and medical claims data for inpatient hospitalizations from the United States (US) from 2016 to 2025. Our results represent probabilistic estimates from five separate models combined using quantile averaging. From 2016 to 2020, there was an annual average of 1,441,808 (95%CI 1,062,630-1,836,536) model-attributed hospitalizations due to the combined burden of influenza, RSV, HMPV, and RV/EV and 46,957 (95%CI 37,389-56,414) model-attributed deaths due to the combined burden of influenza, RSV, and HMPV. The relative burden of specific viruses differed by age group. From 2022 to 2025 this rose to an average of 1,716,865 (95%CI 1,238,382-2,190,080) hospitalizations and 109,996 (95%CI 94,775-125,073) deaths, with the increase driven by SARS-CoV-2. Respiratory viruses, including those vaccine-preventable, are a substantial cause of hospitalization and mortality in the US and their combined burden has increased due to the emergence and persistent circulation of SARS-CoV-2. Continued monitoring of the endemic burden of SARS-CoV-2 is a critical public health priority.