In Partnership with UAlbany, NYSDOH Releases First-in-the-Nation Data & Analysis on COVID-19 Vaccine Effectiveness & Breakthrough Infections

Vials of COVID-19 vaccine, in a row

ALBANY, N.Y. (Aug. 18, 2021) — Working with the University at Albany, the New York State Department of Health today released data on the effectiveness of vaccines in the fight against COVID-19 — showing that vaccinations remain the best way for New Yorkers to protect themselves, families and communities from COVID-19 and its most severe outcomes such as hospitalization.

The first-in-the-nation vaccine effectiveness study, based on actual data, was published by the Centers for Disease Control and Prevention (CDC) and found that unvaccinated New Yorkers were 11 times more likely to be hospitalized and eight times more likely to be diagnosed with COVID-19 than those who were fully vaccinated.

“This NYSDOH-led study demonstrates that state-level COVID-19 surveillance data can be practically analyzed to assess COVID-19 cases and hospitalizations, vaccine coverage, vaccine effectiveness, and rate of breakthrough infections,” said David Holtgrave, dean of the School of Public Health and a co-author on the study. “The data presented here are highly useful for informing COVID-19 prevention efforts including vaccination programs and multi-layered strategies.” 

“The findings of our research are clear: Vaccines provide the strongest protection for New Yorkers against getting infected or becoming hospitalized due to COVID-19,” said senior author and State Health Commissioner Dr. Howard Zucker. “I applaud the research and work done by our scientists and continue to encourage all New Yorkers to get vaccinated as soon as possible. Our study indicates while breakthrough cases of COVID-19 are rare, fully vaccinated New Yorkers still need to remain vigilant as the delta variant has led to increases in COVID-19 cases and hospitalizations. We are proud that our research is informing our federal partners on policy decisions affecting people across the nation.” 

To provide an in-depth analysis of the effectiveness of COVID-19 vaccines, public health scientists and epidemiologists from NYSDOH and UAlbany examined rates of cases and hospitalization among vaccinated New Yorkers aged 18 and older (from “breakthrough” infections) and compared these to rates among unvaccinated, from May 3 to July 25.  

During the emergence of the delta variant and the reduction of social distancing and mask wearing, both unvaccinated and vaccinated adults experienced an increase in COVID-19 cases. However, researchers found vaccines remained about 92% to 95% effective at preventing hospitalizations among the vaccinated. While the effectiveness of the vaccines declined from about 92% to 80% in reducing COVID-19 cases, the study determined that the use of vaccines remains a critically important method in lowering COVID-19 infections and hospitalizations.

“Under Health Commissioner Dr. Howard Zucker’s leadership, we undertook this study to better understand the current situation regarding vaccines, cases and hospitalizations,” said Eli Rosenberg, a lead study author from NYSDOH and an associate professor at UAlbany. “At this important time in the epidemic, we’ve observed a clear increase in cases for unvaccinated and even vaccinated people. Yet these results demonstrate that compared to unvaccinated people, those who are vaccinated remain consistently far more protected against infection and hospitalization. Vaccines remain a critical tool for COVID-19 prevention.”

To get vaccinated, visit NYSDOH's website or call 1-833-NYS-4-VAX (1-833-697-4829) to make an appointment at a state-run site, which are also offering walk-in appointments. New Yorkers can also visit to find a vaccine site nearest them.