Estimated Community Seroprevalence of SARS-CoV-2 Antibodies — Two Georgia Counties, April 28–May 3, 2020

Abstract

this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr).Transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is ongoing in many communities throughout the United States. Although case-based and syndromic surveillance are critical for monitoring the pandemic, these systems rely on persons obtaining testing or reporting a COVID-19-like illness. Using serologic tests to detect the presence of SARS-CoV-2 antibodies is an adjunctive strategy that estimates the prevalence of past infection in a population. During April 28-May 3, 2020, coinciding with the end of a statewide shelter-in-place order, CDC and the Georgia Department of Public Health conducted a serologic survey in DeKalb and Fulton counties in metropolitan Atlanta to estimate SARS-CoV-2 seroprevalence in the population. A two-stage cluster sampling design was used to randomly select 30 census blocks in each county, with a target of seven participating households per census block. Weighted estimates were calculated to account for the probability of selection and adjusted for age group, sex, and race/ethnicity. A total of 394 households and 696 persons participated and had a serology result; 19 (2.7%) of 696 persons had SARS-CoV-2 antibodies detected. The estimated weighted seroprevalence across these two metropolitan Atlanta counties was 2.5% (95% confidence interval [CI] = 1.4-4.5). Non-Hispanic black participants more commonly had SARS-CoV-2 antibodies than did participants of other racial/ethnic groups (p<0.01). Among persons with SARS-CoV-2 antibodies, 13 (weighted % = 49.9; 95% CI = 24.4-75.5) reported a COVID-19-compatible illness,* six (weighted % = 28.2; 95% CI = 11.9-53.3) sought medical care for a COVID-19-compatible illness, and five (weighted % = 15.7; 95% CI = 5.1-39.4) had been tested for SARS-CoV-2 infection, demonstrating that many of these infections would not have been identified through case-based

Susceptibility to SARS-CoV-2 Infection Among Children and Adolescents Compared With Adults

“…A total of 18 studies were contact-tracing studies (CTSs), 7,10,12,16-31 with 3 based in schools, [29][30][31] and 14 studies were population screening studies. 7, [32][33][34][35][36][37][38][39][40][41][42][43][44][45] Two were high quality, 33,35 22 were medium quality, 10,12,16,21,22,[24][25][26][27][29][30][31][32]34,36,38,[40][41][42][43][44][45] 7 were low quality, [17][18][19][20]23,28,39 and 1 was uncertain quality. 7,37…”

“…Data from prevalence studies for children and adolescents compared with adults are shown in Figure 4. 7, [32][33][34][35][36][38][39][40][41][42][43][44][45] We did not undertake a meta-analysis of population screening studies given the important differences in the populations, epidemic time points, and methodologies involved.…”

“…35 A total of 10 studies reported seroprevalence, 7,36,38-45 3 being nationally representative. 7,36,38 A lower seroprevalence was identified in children and in some adolescents compared with adults in a number of studies, including a nationally representative study in Spain (ENE-COVID), 36 a Dutch nationally representative study (PIENTER Corona study), 7,37 and city or regional studies from Iran, 39 the US, 40 Switzerland, 41 and Japan, 42 although no difference by age was found in a survey in 133 sentinel cities in 26 Brazilian states. 38 Two community-based studies following localized outbreaks found lower seroprevalence among children and adolescents than adults in Lombardy, Italy, 43 and Thuringia, Germany, 44 with a second German postoutbreak study 45 finding no overall association with age.…”

Seroprevalence of SARS-CoV-2 antibodies and associated factors in health care workers: a systematic review and meta-analysis

“…We found that the overall seroprevalence was 8.7% with a wide range among studies from 0% to 45.3%. Population-based and community-based studies in USA showed a great variability in seroprevalence of SARS-CoV-2 antibodies from 1.1% to 14.4% [63][64][65][66][67]. Similar studies in Europe [68][69][70] and China [71] found very different seroprevalence in general population ranging from 0.23% to 10.9%.…”

High titers of multiple antibody isotypes against the SARS-CoV-2 spike receptor-binding domain and nucleoprotein associate with better neutralization

“…Thus, it is essential that we carefully study and document the neutralizing antibody responses in recovered individuals. SARS-CoV-2 antibody testing is critical to understanding who has been infected and to provide a picture of seroprevalence in a community [4][5][6][7][8][9] . However, while these tests are important and provide a relative antibody titer, they are seen more as a "yes or no" type of answer to whether an individual has been infected.…”