SARS-CoV-2 is commonly transmitted in the household, and the risk of converting to a case after a household exposure is generally higher than in other settings, largely reflecting the challenges of quarantine and isolation for persons living in the same dwelling. Whittemore, et al. (2022) analyzed data from more than 600,000 household contacts in New York City (NYC) to characterize the risks of acquiring infection after household exposure.

During August 1, 2020, to July 31, 2021, of 605,849 household contacts identified, 165,487 (27.3%) were women, 133,724 (22.1%) were men, 56,665 (9.4%) were Black, 121,233 (20.0%) were Hispanic or Latino, 72,976 (12.0%) were White, and 145,899 (24.1%) converted to a case within 2 to 10 days after the first exposure date to the index case while infectious.

The following groups had higher odds of converting to a case: persons with a gender identity of female or woman/girl, persons with a gender identity of transgender/nonbinary or genderqueer/gender identity not listed; Asian and Hispanic or Latino persons; intimate partners, children or siblings of a case; persons exposed to a symptomatic case. Comorbidities associated with higher odds of converting from a household contact to a case included history of diabetes, heart attack, hypertension, immunosuppression, lung disease, and being overweigh. For each increase in the percentage of persons in the household contact’s age group who were vaccinated against COVID-19, the odds of converting to a case decreased by 1%.

Reference: Whittemore K, et al. Evaluation of Risk Factors for Conversion From a COVID-19 Household Contact to a Case in New York City, August 1, 2020, to July 31, 2021. JAMA Netw Open. 2022;5(9):e2233001. doi:10.1001/jamanetworkopen.2022.33001