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It is imperative to advance our understanding of heterogeneities in the transmission of SARS-CoV-2 such as age-specific infectiousness and superspreading. To this end, it is important to exploit multiple data streams that are becoming abundantly available during the pandemic. In this paper, we formulate an individual-level spatiotemporal mechanistic framework to integrate individual surveillance data with geolocation data and aggregate mobility data, enabling a more granular understanding of the transmission dynamics of SARS-CoV-2.We analyze reported cases, between March and early May 2020, in five (urban and rural) counties in the state of Georgia. First, our results show that the reproductive number reduced to below one in about 2 wk after the shelter-in-place order. Superspreading appears to be widespread across space and time, and it may have a particularly important role in driving the outbreak in rural areas and an increasing importance toward later stages of outbreaks in both urban and rural settings. Overall, about 2% of cases were directly responsible for 20% of all infections. We estimate that the infected nonelderly cases (<60 y) may be 2.78 [2.10, 4.22] times more infectious than the elderly, and the former tend to be the main driver of superspreading. Our results improve our understanding of the natural history and transmission dynamics of SARS-CoV-2. More importantly, we reveal the roles of age-specific infectiousness and characterize systematic variations and associated risk factors of superspreading. These have important implications for the planning of relaxing social distancing and, more generally, designing optimal control measures.

Global food security is a major driver of population health, and food system collapse may have complex and long-lasting effects on health outcomes. We examined the effect of prenatal exposure to the Great Chinese Famine (1958–1962)—the largest famine in human history—on pulmonary tuberculosis (PTB) across consecutive generations in a major center of ongoing transmission in China. We analyzed >1 million PTB cases diagnosed between 2005 and 2018 in Sichuan Province using age–period–cohort analysis and mixed-effects metaregression to estimate the effect of the famine on PTB risk in the directly affected birth cohort (F1) and their likely offspring (F2). The analysis was repeated on certain sexually transmitted and blood-borne infections (STBBI) to explore potential mechanisms of the intergenerational effects. A substantial burden of active PTB in the exposed F1 cohort and their offspring was attributable to the Great Chinese Famine, with more than 12,000 famine-attributable active PTB cases (>1.23% of all cases reported between 2005 and 2018). An interquartile range increase in famine intensity resulted in a 6.53% (95% confidence interval [CI]: 1.19–12.14%) increase in the ratio of observed to expected incidence rate (incidence rate ratio, IRR) in the absence of famine in F1, and an 8.32% (95% CI: 0.59–16.6%) increase in F2 IRR. Increased risk of STBBI was also observed in F2. Prenatal and early-life exposure to malnutrition may increase the risk of active PTB in the exposed generation and their offspring, with the intergenerational effect potentially due to both within-household transmission and increases in host susceptibility

Serological testing remains a passive component of the public health response to the COVID-19 pandemic. Using a transmission model, we examine how serological testing could have enabled seropositive individuals to increase their relative levels of social interaction while offsetting transmission risks. We simulate widespread serological testing in New York City, South Florida, and Washington Puget Sound and assume seropositive individuals partially restore their social contacts. Compared to no intervention, our model suggests that widespread serological testing starting in late 2020 would have averted approximately 3300 deaths in New York City, 1400 deaths in South Florida and 11,000 deaths in Washington State by June 2021. In all sites, serological testing blunted subsequent waves of transmission. Findings demonstrate the potential benefit of widespread serological testing, had it been implemented in the pre-vaccine era, and remain relevant now amid the potential for emergence of new variants. Serological testing remains a passive component of the current public health response to the COVID-19 pandemic. Using a mathematical model, the authors examine how testing for antibodies could have enabled policies in which seropositive individuals increased their relative levels of social interaction while offsetting transmission risks

Observational evidence of COVID-19 vaccine effectiveness (VE) against SARS-CoV-2 infection is often limited by differences in testing behavior between vaccinated and unvaccinated persons. This study aimed to estimate VE against SARS-CoV-2 infection among students using data from a school district opt-in weekly testing program. An observational, matched cohort study to emulate a target vaccine trial was conducted among students attending an urban school district in the Southeastern United States. Between 9/7/21 and 5/26/22, 9172 children, among 24,188 total students participating in the testing program, were followed from vaccination date, determined by state immunizations information systems (IIS) records, to first positive SARS-CoV-2 rapid antigen test, regardless of symptoms, conducted through the testing program. Hazard ratios and their 95 % confidence intervals were calculated using Cox proportional hazards models, and VE was calculated as (1-hazard ratio)*100. All analyses were stratified by age group (5–11 years and 12 years and older) and sensitivity analyses were conducted. Among students aged 5–11 years, VE against SARS-CoV-2 infection within 60 days of first dose of any COVID-19 vaccine was 42.9 % (95 % CI, 7.1 % to 78.7 %) and waned to 20.7 % (95 %, CI 0.0 % to 41.8 %) by 180 days. Over the full study period, VE against SARS-CoV-2 infection was 14.9 % (95 % CI, −5.0 % to 34.7 %). Among students 12 years and older, VE against SARS-CoV-2 infection was −5.0 % (95 % CI, −37.0 % to 26.5 %) over the full study period. Insufficient data was available to estimate VE within 60 days of vaccination in this age group. Among 5–11 year olds participating in a routine SARS-CoV-2 surveillance testing program, VE against SARS-CoV-2 infection was modest immediately following vaccination but waned over the school year. This analysis limits biases found in traditional VE studies related to differential testing behaviors and allows estimation of VE against infection, regardless of symptoms. •Unique dataset of school district opt-in weekly SARS-CoV-2 testing program data.•Target trial emulation approach to limit bias often in observational studies.•Estimates VE against infection, both symptomatic and asymptomatic.•Modest VE found among students 5–11 years old, which waned over school year.

Infectious diseases account for nearly half of all child mortality worldwide, with most of the burden concentrated in low and middle-income countries (LMIC). Person-to-person interactions, or ‘contacts’, facilitate the spread of respiratory and enteric pathogens. The number and nature of contacts likely vary across countries along with social and cultural norms, but few studies have compared behaviors across countries and none have done so with a focus on children. Here we present data from a population-based study conducted from 2021 to 2023 in Guatemala, India, Mozambique, and Pakistan. Across four countries, 5085 participants reported a total of 84,829 contacts across two days. Mean contact rates were highest among 10- to 19-year-olds except in Pakistan, where contacts were highest among 5- to 9-year-olds. Non-home locations which presented high risk for transmission were schools in India, workplaces in Pakistan, and ‘other’ social / leisure locations in Mozambique and Guatemala. Among children under 5 years of age, the proportion of contacts with non-household members was highest in Mozambique and lowest in India; most of these were reported at home. Contact patterns by age diverge from prior projections that are extrapolated from contact data from high-income countries, underscoring the value of local data collection. Social contact data are important for modelling epidemic transmission dynamics but limited data are available for lower- and middle-income countries. Here, the authors present social contact data in Guatemala, India, Mozambique and Pakistan collected in 2021-2023.

•Reviewed interventions focused on improving access to and utilization of immunization services.•Simple, strategic changes had impacts on immunization uptake.•Reaching Every District (RED) strategies can be successfully tailored to urban settings.•Few studies have assessed interventions designed explicitly for urban areas. Immunization programs in developing countries increasingly face challenges to ensure equitable delivery of services within cities where rapid urban growth can result in informal settlements, poor living conditions, and heterogeneous populations. A number of strategies have been utilized in developing countries to ensure high community demand and equitable availability of urban immunization services; however, a synthesis of the literature on these strategies has not previously been undertaken. We reviewed articles published in English in peer-reviewed journals between 1990 and 2013 that assessed interventions for improving routine immunization coverage in urban areas in low- and middle-income countries. We categorized the intervention in each study into one of three groups: (1) interventions aiming to increase utilization of immunization services; (2) interventions aiming to improve availability of immunization services by healthcare providers, or (3) combined availability and utilization interventions. We summarized the main quantitative outcomes from each study and effective practices from each intervention category. Fifteen studies were identified; 87% from the African, Eastern Mediterranean and Southeast Asian regions of the World Health Organization (WHO). Six studies were randomized controlled trials, eight were pre- and post-intervention evaluations, and one was a cross-sectional study. Four described interventions designed to improve availability of routine immunization services, six studies described interventions that aimed to increase utilization, and five studies aiming to improve both availability and utilization of services. All studies reported positive change in their primary outcome indicator, although seven different primary outcomes indicators were used across studies. Studies varied considerably with respect to the type of intervention assessed, study design, and length of intervention assessment. Few studies have assessed interventions designed explicitly for the unique challenges facing immunization programs in urban areas. Further research on sustainability, scalability, and cost-effectiveness of interventions is needed to fill this gap.

KwaZulu-Natal province, South Africa, has among the highest burden of XDR TB worldwide with the majority of cases occurring due to transmission. Poor access to health facilities can be a barrier to timely diagnosis and treatment of TB, which can contribute to ongoing transmission. We sought to determine the geographic distribution of XDR TB patients and proximity to health facilities in KwaZulu-Natal. We recruited adults and children with XDR TB diagnosed in KwaZulu-Natal. We calculated distance and time from participants' home to the closest hospital or clinic, as well as to the actual facility that diagnosed XDR TB, using tools within ArcGIS Network analyst. Speed of travel was assigned to road classes based on Department of Transport regulations. Results were compared to guidelines for the provision of social facilities in South Africa: 5km to a clinic and 30km to a hospital. During 2011-2014, 1027 new XDR TB cases were diagnosed throughout all 11 districts of KwaZulu-Natal, of whom 404 (39%) were enrolled and had geospatial data collected. Participants would have had to travel a mean distance of 2.9 km (CI 95%: 1.8-4.1) to the nearest clinic and 17.6 km (CI 95%: 11.4-23.8) to the nearest hospital. Actual distances that participants travelled to the health facility that diagnosed XDR TB ranged from <10 km (n = 143, 36%) to >50 km (n = 109, 27%), with a mean of 69 km. The majority (77%) of participants travelled farther than the recommended distance to a clinic (5 km) and 39% travelled farther than the recommended distance to a hospital (30 km). Nearly half (46%) of participants were diagnosed at a health facility in eThekwini district, of whom, 36% resided outside the Durban metropolitan area. XDR TB cases are widely distributed throughout KwaZulu-Natal province with a denser focus in eThekwini district. Patients travelled long distances to the health facility where they were diagnosed with XDR TB, suggesting a potential role for migration or transportation in the XDR TB epidemic.

The COVD-19 pandemic has led to major impacts on population-level transmission of respiratory viral illnesses. However, the impact of the pandemic on Mycobacterium tuberculosis transmission is unknown. Schoolchildren from 12 cities in Jiangsu Province were administered tuberculin skin tests at school matriculation from 2017–2021. We conducted an interrupted time-series analysis to compare trends from annual tuberculin surveys before (2017–2019) and during pandemic-related social restrictions (2020–2021). We compared observed trends in tuberculin positivity during restrictions to a counterfactual model assuming background trends prior to restrictions continued linearly. From 2017–2021, 1,940,735 schoolchildren from 1,427 schools were administered a skin test. Among middle school students, tuberculin positivity was largely consistent from 2017–2019 (9.3%, 9.6%, 10.0%), but reduced in 2020 and 2021 (8.0% and 7.0%). There was a reduction in the annual risk of infection of 24.7% (95% predictive interval [PI], −27.2, −21.2) and 37.0% (95% PI, −40.8, −33.3) compared to the counterfactual model in 2020 and 2021. Among high school students, similar but more modest reductions in the annual risk of infection were seen in post-pandemic years (19.8% reduction in 2021). There have been substantial population-level decreases in M tuberculosis transmission among adolescents in eastern China. The impact of the COVID pandemic restrictions on Mycobacterium tuberculosis transmission is not well understood. Here, the authors analyse tuberculin skin test results from school children in Jiangsu Province, China and find evidence of declined transmission during the pandemic compared to the years before.