As COVID-19 cases increase along with spread of the more transmissible Delta variant, the effectiveness of COVID-19 vaccines continues to be an important topic. A new KFF analysis looks at COVID-19 vaccine “breakthrough cases,” when fully vaccinated individuals become infected, as well as hospitalizations and deaths, to see which states are providing data on breakthrough events, how regularly, and what those data reveal.
After a review of the websites of all states and D.C. and other official sources, the new analysis found that half of states (25) report some data on COVID-19 breakthrough events. Within that, 15 states report these data on a weekly basis and one state reports on a daily basis, while the other nine report more infrequently. Overall, the data found that breakthrough events are extremely rare among those who are fully vaccinated, and that the vast majority of reported COVID-19 cases, hospitalizations, and deaths in U.S. are among those who are unvaccinated or not fully vaccinated. Some key highlights include:
This analysis highlights how rare breakthrough events are but also how data remain limited, and only available for a subset of states.