key: cord-0699946-ds4hljc3
authors: Werzberger, Alan; Carreño, Juan Manuel; Team, Sinai Serocore; Polinger, Adam; Krammer, Florian; Zachariah, Philip
title: Household level SARS-CoV-2 sero-epidemiology in a high prevalence group of adults and children-implications for community infection control
date: 2021-08-20
journal: Am J Infect Control
DOI: 10.1016/j.ajic.2021.08.015
sha: 53543d202a2be2aeef37613e9f03b931558f9445
doc_id: 699946
cord_uid: ds4hljc3

In 108 households (n=474, 280 ≤ 18 years old), SARS-CoV-2 seroprevalence was significantly associated with age (range 37.5 -78.7%) and lowest in children ≤ 10 years old. Among 92 households with members ≤ 18, 14 (15.2%) had only a seropositive child or adolescent, while 16 (17.4%) had only seropositive adults. Households with both groups concurrently seropositive (n=62) were larger in size (mean 8.11+/- 2.49) vs. (mean 5.77 +/- 2.31) (p<0.001).

The sero-epidemiology of Coronavirus disease 2019 (COVID-19) at a household level has been assessed through screening contacts of medically attended adult index cases, using cohorts with limited numbers of infected children, and/or outside the US. [1] [2] [3] We report severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in a random group of large households sampled in the community.

This study was conducted in an orthodox Jewish village in New York State, led by the local community health center and approved by the Western Institutional Review Board. A random sample of households from the community directory were invited to participate. After informed consent and assent, a phone survey ascertained household composition, overall compliance with preventive measures, history of COVID-19 symptomatology and medically attended disease in household members. Households with currently symptomatic members were excluded. Serum samples for individuals in recruited households were collected at the local health center. SARS-CoV-2 serology was measured using a previously validated assay. 4, 5 Chi-squared or Fischer's exact tests were used to compare proportions, and one-way ANOVA with Tukey multiple comparisons tests used to compare continuous variables. Analyses were performed using R version 4.0.0 (R Foundation for Statistical Computing).

Interviews and sample collection were done from January 3 rd , 2021 and January 21 st , 2021.

Among 6,800 households in the directory, 300 were invited to participate and 108 were enrolled, consisting of 724 individuals. Median household size in the enrolled sample was 6.5 (IQR: [4] [5] [6] [7] [8] [9] . No households reported COVID-19 related hospitalizations or deaths. While all households reported members with COVID-19 symptoms in the past three months rarely was the first symptomatic person ≤ 18 years ( 51.8%+/-0.18, p =0.02). Quantitative IgG levels were significantly higher in older adults (Figure 1) but IgM levels were similar across age groups. antibodies against the recombinant full-length spike. Stratification by age (X axis) of antibody endpoint titers (Y axis) is presented. Ordinary one-way ANOVA with Tukey multiple comparisons tests is shown.

In this analysis of one of the largest community-based samples of SARS-CoV-2 infected children in the US, few children were diagnosed previously, and symptomatic index cases were mostly adults.

This confirms that the bulk of pediatric SARS-CoV-2 infections 6 are not medically attended, and that active case detection is required. Exposure risk to children in this close-knit community is high, 7 which could explain higher pediatric seroprevalence rates compared to previous data. 1 The significantly lower seroprevalence rate noted in < 10 year-olds may reflect less susceptibility to household SARS-CoV-2 exposure, strengthening an emerging hypothesis from tracing and community-level serosurveys. 8 been demonstrated previously. Seroconcordant households also had a higher proportion of adolescents and adults, both potentially more vulnerable groups based on these data. Serum IgG levels were the highest in older adults, as observed previously, 9 but antibody levels were mostly comparable across age groups, a finding that gives context to potentially divergent antibody responses based on age in severe disease. 10 This study is limited by the lack of accurate timing of index infection but evidence of robust antibody responses in children even after mild or asymptomatic infection strengthens our conclusion of different seropositivity rates. 11 Another limitation is the difference in enrolled proportions between groups but this is less likely to cause a systematic bias that changes the conclusions.

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