Whaley CM, Cantor J, Pera M, et al. - Researchers herein aimed at determining the association, if any, between household birthdays, which likely correspond to informal social gatherings, and COVID-19 infection. In this cross-sectional study, they performed comparison of COVID-19 infections between households with and without a birthday in the preceding 2 weeks, stratified according to county-level COVID-19 prevalence in that week and adjusting for household size and both week- and county-specific differences, using nationwide data from 2.9 million US households with private insurance. Findings revealed 8.6 more diagnoses per 10,000 individuals among households with birthdays vs those without a birthday, a relative increase of 31% of county-level prevalence, an increase in COVID-19 diagnoses of 15.8 per 10,000 persons after a child birthday, and an increase in COVID-19 diagnoses of 5.8 per 10 000 among households with an adult birthday. Per these findings, events that result in small and informal social gatherings, such as birthdays, and in particular, children’s birthdays, play a potential role as a source in SARS-CoV-2 transmission.