Susceptibility and infectiousness of SARS-CoV-2 in children versus adults, by variant (wild-type, Alpha, Delta): a systematic review and meta-analysis of household contact studies (preprint)

Importance: Understanding the susceptibility and infectiousness of children and adolescents in comparison to adults is important to appreciate their role in the COVID-19 pandemic. Objective: To determine SARS-CoV-2 susceptibility and infectiousness of children and adolescents with adults as comparator for three variants (wild-type, Alpha, Delta) in the household setting. We aimed to identify the effects independent of vaccination. Data Sources: We searched EMBASE, PubMed and medRxiv up to January 2022. Additional studies were identified through contacting subject experts. Study Selection: Two reviewers independently identified studies providing secondary attack rates (SAR) for SARS-CoV-2 infection in children (0-9 years), adolescents (10-19 years) or both compared with adults (20 years and older) derived from household data. Data Extraction and Synthesis: Two reviewers independently performed data extraction. We assessed risk of bias of included studies using a critical appraisal checklist and a random-effects meta-analysis model to pool association estimates. Main Outcomes and Measures: Odds ratio (OR) for SARS-CoV-2 infection comparing children and adolescents with adults stratified by wild-type, Alpha, and Delta variant, respectively. Susceptibility was defined as the secondary attack rate (SAR) among susceptible household contacts irrespective of the age of the index case. Infectiousness was defined as the SAR irrespective of the age of household contacts when children/adolescents/adults were the index case. Results: Twenty-eight studies (308,857 contacts) were included in the susceptibility analysis, for Delta only one (large) study was available. Compared to adults children and adolescents were less susceptible to the wild-type and Delta variant, but equally susceptible to the Alpha variant. In the infectiousness analysis, 21 studies (201,199 index cases) were included. Compared to adults, children and adolescents were less infectious when infected with the wild-type and Delta variant. Alpha variant-related infectiousness remained unclear, 0-9 year old children were at least as infectious as adults. SAR among household contacts was highest during circulation of the Alpha variant, lowest during wild-type circulation and intermediate during Delta circulation. Conclusions and Relevance: When considering the potential role of children and adolescents, for each variant susceptibility, infectiousness, age group and overall transmissibility need to be assessed to guide public health policy.

Pandemic-EBT and grab-and-go school Meals: Costs, reach, and benefits of two approaches to keep children fed during school closures due to COVID-19 (preprint)

ABSTRACT Importance School meals improve nutrition and health for millions of U.S. children. School closures due to the COVID-19 pandemic disrupted children’s access to school meals. Two policy approaches were activated to replace missed meals for children from low-income families. The Pandemic Electronic Benefit Transfer (P-EBT) program provided the cash value of missed meals directly to families on debit-like cards to use for making food purchases. The grab-and-go meals program offered prepared meals from school kitchens at community distribution points. The effectiveness of these programs at reaching those who needed them and their costs were unknown. Objective To determine how many eligible children were reached by P-EBT and grab-and-go meals, how many meals or benefits were received, and how much each program cost to implement. Design Cross-sectional study, Spring 2020. Setting National. Participants All children <19 years old and children age 6-18 eligible to receive free or reduced price meals (FRPM). Exposure(s) Receipt of P-EBT or grab-and-go school meals. Main Outcome(s) and Measure(s) Percentage of children reached by P-EBT and grab-and-go school meals; average benefit received per recipient; and average cost, including implementation costs and time costs to families, per meal distributed. Results Grab-and-go school meals reached about 10.5 million children (17% of all US children), most of whom were FRPM-eligible students. Among FRPM-eligible students only, grab-and-go meals reached 27%, compared to 89% reached by P-EBT. Among those receiving benefits, the average monthly benefit was larger for grab-and-go school meals ($148) relative to P-EBT ($110). P-EBT had lower costs per meal delivered - $6.51 - compared to $8.20 for grab- and-go school meals. P-EBT had lower public sector implementation costs but higher uncompensated time costs to families (e.g., preparation time for meals) compared to grab-and-go school meals. Conclusions and Relevance Both programs supported children’s access to food when schools were closed and in complementary ways. P-EBT is an efficient and effective policy option to support food access for eligible children when school is out. KEY POINTS Question What were the operating costs, costs and benefits to families, and proportion of eligible children who received benefits of two programs aimed at replacing school meals missed when schools were closed due to COVID-19? Findings In this cross sectional analysis, we found that the Pandemic-Electronic Benefit Transfer program, in which state agencies sent debit cards loaded with the cash value of missed school meals directly to families, reached nearly all low income students (89%) and cost relatively little per meal provided. In comparison, grab-and-go school meals, in which school food service departments provided prepared meals for offsite consumption, reached 27% of low income children and was associated with larger per meal costs. Meaning During times when children cannot access school meals, state and federal agencies should support cost-efficient programs for schools to distribute prepared meals and activate programs like P-EBT to efficiently reach eligible children.

High prevalence of previous infection with SARS-CoV-2 and persistent symptoms at a large university (preprint)

Importance: Universities are unique settings with large populations, congregate housing, and frequent attendance of events in large groups. However, the prevalence of previous infection with SARS-CoV-2 in university students, including symptomatic and asymptomatic disease, is unknown. Objective: To determine the prevalence of previous infection, risk factors for infection, and the prevalence of persistent symptoms following infection among university students. Design: This was a cross-sectional study that surveyed students about demographics, risk factors, and symptoms, and simultaneously tested their saliva for IgA antibodies to SARS-CoV-2. To estimate the prevalence of previous infection we adjusted our intentional sample of a diverse student population for year in school and age to resemble the composition of the entire student body, and adjusted for the imperfect sensitivity and specificity of the antibody test. Univariate and multivariate analysis was used to identify independent risk factors for infection. Setting: A large public university in Athens, Georgia between January 22 and March 22, 2021. Participants: Undergraduate and graduate students; 488 completed the survey, 432 had a valid antibody result. and 428 had both. Exposure: Previous infection with SARS-CoV-2 based on measurement of IgA antibodies in saliva and adjustment for sample characteristics and test accuracy. Main Outcomes and Measures: The primary outcome was the estimated prevalence of previous infection with SARS-CoV-2. Secondary outcomes were independent risk factors for infection, and the prevalence of persistent symptoms among persons reporting a previous symptomatic infection. Results: The estimated prevalence of previous infection for 432 participants with valid antibody results was between 41% and 42%. Independent risk factors for infection included male sex, having a roommate with a known symptomatic infection, and having 2 or fewer roommates. More frequent attendance of parties and bars was a univariate risk factor, but not in the multivariate analysis. Of 122 students reporting a previous symptomatic infection, 14 (11.4%) reported persistent symptoms a median of 132 days later. Conclusions and Relevance: Previous infection with SARS-CoV-2, both symptomatic and asymptomatic, was common at a large university. Measures that could prevent resurgence of the infection when students return to campus include mandatory vaccination policies, mass surveillance testing, and testing of sewage for antigen to SARS-CoV-2.

Transmission roles of symptomatic and asymptomatic COVID-19 cases: a modeling study (preprint)

ObjectiveAge-dependent asymptomatic and symptomatic transmission dynamics of COVID-19 have not been well quantified due to limited data. MethodsThrough a population-based surveillance network, we collected data on 1342 confirmed cases with a 90-days follow-up for all asymptomatic cases. ResultsThe difference in transmissibility of a symptomatic and asymptomatic case depended on age and was most distinct for the middle-age groups. The asymptomatic cases had a 66.72% lower transmissibility rate than symptomatic cases, and 74.10% (95%CI: 65.85% - 80.72%) of all asymptomatic cases were missed in detection. The average proportion of asymptomatic cases was 28.22% (95%CI: 22.97% - 34.56%). Simulation showed that the burden of asymptomatic transmission increased as the epidemic continued and could potentially dominate the spreading. ConclusionAsymptomatic COVID-19 cases play a significant role in transmission. Vaccine Strategies prioritizing the population between 30-60 years old are likely to have the most population-level benefits.

Estimation of case-fatality rate in COVID-19 patients with hypertension and diabetes mellitus in the New York State (preprint)

We estimated the case-fatality rate (CFR) and ratios (RR) in adult COVID-19 cases with hypertension and diabetes mellitus in the New York State. We found that the elderly population had a higher CFR, but the elevated CFR ratios associated with comorbidities are more pronounced for the younger population.

Spread and control of COVID-19 in China and their associations with population movement, public health emergency measures, and medical resources (preprint)

ABSTRACT BACKGROUND The COVID-19 epidemic, first emerged in Wuhan during December 2019, has spread globally. While the mass population movement for Chinese New Year has significantly influenced spreading the disease, little direct evidence exists about the relevance to epidemic and its control of population movement from Wuhan, local emergency response, and medical resources in China. METHODS Spearman's correlation analysis was performed between official data of confirmed COVID-19 cases from Jan 20th to Feb 19th, 2020 and real-time travel data and health resources data. RESULTS There were 74,675 confirmed COVID-19 cases in China by Feb 19th, 2020. The overall fatality rate was 2.84%, much higher in Hubei than in other regions (3.27% vs 0.73%). The index of population inflow from Hubei was positively correlated with total (Provincial r=0.9159, p<0.001; City r=0.6311, p<0.001) and primary cases (Provincial r=0.8702, p<0.001; City r=0.6358, p<0.001). The local health emergency measures (eg, city lockdown and traffic control) were associated with reduced infections nationwide. Moreover, the number of public health employees per capita was inversely correlated with total cases (r=-0.6295, p<0.001) and infection rates (r=-0.4912, p<0.01). Similarly, cities with less medical resources had higher fatality (r=-0.4791, p<0.01) and lower cure rates (r=0.5286, p<0.01) among the confirmed cases. CONCLUSIONS The spread of the COVID-19 in China in its early phase was attributed primarily to population movement from Hubei, and effective governmental health emergency measures and adequate medical resources played important roles in subsequent control of epidemic and improved prognosis of affected individuals.