Vaccination rates are changing globally, making it challenging for organizers to predict vaccination levels for group meetings being planned. We have created a
browser app to estimate the numbers of unvaccinated, partially vaccinated, and fully vaccinated people in a group at a future date, based on data from around the world on vaccination rates by location and age group. While most accurate over short time frames, this app provides event organizers a clearer picture of the susceptibility of their participants to COVID-19.