SARS-CoV-2 Seroprevalence and Symptom Onset in Culturally Linked Orthodox Jewish Communities Across Multiple Regions in the United States.

Importance: Data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in the United States are still emerging. Objective: To elucidate SARS-CoV-2 seroprevalence and symptom onset in a culturally linked community across 5 states in the United States. Design, Setting, and Participants: This cross-sectional study included adults (aged ≥18 years) recruited from the orthodox Jewish community across 5 states (California, Connecticut, Michigan, New Jersey, and New York) in 3 geographically distinct areas of the United States between May 13 and July 6, 2020. Participants completed an online survey and underwent SARS-CoV-2 antibody testing. Main Outcomes and Measures: Seroprevalence and date of symptom onset of SARS-CoV-2. Results: Overall, 9507 adults (mean [SD] age, 39.6 [15.0] years; 3777 [39.7%] women) completed the SARS-CoV-2 survey, of whom 6665 (70.1%) had immunoglobin G anti-SARS-CoV-2 antibody levels assessed. A high seroprevalence of SARS-CoV-2 antibodies was observed across all communities, with the highest proportion of positive testing observed in New Jersey (1080 of 3323 [32.5%]) and New York (671 of 2196 [30.6%]). Most individuals with a positive SARS-CoV-2 immunoglobin G antibody test reported a date of symptom-onset between March 9 and March 31, 2020 (California: 135 of 154 [87.7%]; Connecticut: 32 of 34 [94.1%]; Michigan: 44 of 50 [88.0%]; New Jersey: 964 of 1168 [82.5%]; New York: 571 of 677 [84.3%]). This start date was coincident with the Jewish festival of Purim, celebrated March 9 to 10, 2020, with extensive intracommunity spread in the weeks following (mean and mode of peak symptom onset, March 20, 2020), occurring in the absence of strong general and culture-specific public health directives. Conclusions and Relevance: This cross-sectional study of orthodox Jewish adults across the US found that socioculturally bound communities experienced early parallel outbreaks in discrete locations, notably prior to substantive medical and governmental directives. Further research should clarify optimal national, local, community-based, and government policies to prevent outbreaks in social and cultural communities that traditionally gather for holidays, assemblies, and festivals.