V-safe

V-safe is an active surveillance system for monitoring COVID-19 vaccination safety administered by the US Centers for Disease Control and Prevention (CDC). Participation in this active surveillance system is open to all people in the USA and its territories who receive a COVID-19 vaccination and who can access v-safe using a smartphone. Respondents self-enrol and receive text-message reminders to complete surveys at specified intervals after vaccination.¹⁰ For days 0–7 after each dose, the survey asks about local and systemic reactions and allows submission of an unstructured text response to the following prompt: “any other symptoms or health conditions you want to report”. For weeks 2–6 and months 3, 6, and 12 after the dose, the survey allows an unstructured text response to the following prompt: “since your/their last check-in, have you/they experienced any new or worsening symptoms or health conditions? (If yes) Please describe.” When respondents log another dose in their account, survey timing restarts.