COVID-19 Breakthrough Data

Note: This page was archived on 5/17/2023 with the end of the Public Health Emergency.

Vaccine breakthrough cases are defined as instances in which an individual tested positive for COVID-19 after being fully-vaccinated (more than 14 days after completing their primary series). This report details the levels of such cases, and hospitalizations among fully-vaccinated people, in New York State. This information has been ascertained by matching records in statewide immunization databases with statewide testing and daily hospital reporting systems.

These findings demonstrate that such cases and hospitalizations have occurred in New York State at levels substantially lower than among unvaccinated people. The estimated high protective effect of vaccines against confirmed infection, and even higher effect for hospitalization, agree with findings from clinical and population studies conducted around the world.

Updates to this breakthrough data report will be published approximately weekly and include data through the designated "as of" date.

As of data received through May 8, 2023, the New York State Department of Health is aware of:

• 2,823,097 laboratory-confirmed breakthrough cases of COVID-19 among fully-vaccinated people in New York State, which corresponds to 19.1% of the population of fully-vaccinated people 5-years or older.
• 119,202 hospitalizations with COVID-19 among fully-vaccinated people in New York State, which corresponds to 0.81% of the population of fully-vaccinated people 5-years or older.  

To understand the above statistics, it is important to consider that they reflect not only the effectiveness of vaccines, but also changes over time in the intensity of the epidemic, circulating variant strains (such as Omicron), and protective behaviors (e,g, masking and social distancing) against COVID-19, as well as the growing number of people fully-vaccinated in New York State.

To measure the real-world effectiveness of vaccines in reducing cases and hospitalizations, compared to unvaccinated people, additional information and analyses are necessary. One approach is to compare the rates of cases and hospitalizations among vaccinated people to the rates of these outcomes in unvaccinated people, over time.

The next section shows these comparisons among adult residents of NYS, building on previously published methods.

Table 1: New cases and new hospitalizations with laboratory-confirmed COVID-19 among fully vaccinated and unvaccinated adults, age 18 years or older.

*Grey shading has been applied to recent weeks for which data are still accruing, with a darker grey representing data with the largest amount of uncertainty. Estimates in darker grey are likely an undercount and are subject to most change.

*Grey shading has been applied to recent weeks for which data are still accruing, with a darker grey representing data with the largest amount of uncertainty. Estimates in darker grey are likely an undercount and are subject to most change.

*Grey shading has been applied to recent weeks for which data are still accruing, with a darker grey representing data with the largest amount of uncertainty. Estimates in darker grey are likely an undercount and are subject to most change.

Please refer to our publication in MMWR for a description of the data sources, analytic methods, methodological considerations and limitations of this work.

Additionally:

• For the purposes of this analysis, cases and hospital admissions are defined at the event-level (multiple cases and hospital admissions with COVID-19 possible per person).
• All estimates in this report are preliminary and subject to change. In order to confirm vaccination status at the time of diagnosis and/or hospitalization, the dates of these events must be evaluated, as opposed to the dates these cases were reported to NYS DOH. Because of this requirement and ongoing data submissions of infections, hospitalizations, and vaccinations within each respective database, it is expected that historical estimates may need minor changes as this report is updated to provide a timely snapshot of the epidemic.
• In this analysis, fully-vaccinated is defined as an individual who:
  • Has received one of the three vaccines currently authorized by the US Food and Drug Administration (FDA): Pfizer-BioNTech, Moderna, and Janssen/Johnson & Johnson.
  • Is 14 days or more past the final dose of their original 2-dose (Pfizer-BioNTech, Moderna) or 1-dose (Janssen/Johnson & Johnson) series.
• Fully-vaccinated people may have received additional or booster doses, which are not specifically accounted for in this analysis.
• On 7/8/22 case and hospitalization data were updated to correct a reporting error.
• As of 7/12/22, The definition for breakthrough cases has been updated to align with repeat infections.
  • The previous breakthrough definition utilized only one positive test per person (vaccinated and non-vaccinated). The new definition   includes repeat infections that meet the following criteria:
    • It has been 90 days since the first positive result for the person, regardless of whether or not the person had a positive test between the two results.
    • It has been 90 days since the repeat positive result for the person, regardless of whether or not the person had a positive test between the two results.
  • Previously only the most recent infection was counted, and as outlined in the MMWR a “new COVID-19 case was defined as the receipt of a new positive SARS-CoV-2 NAAT or antigen test result, but not within 90 days of a previous positive result”. Now the first one is always counted and each positive test 90 days after the last one is counted as a repeat infection.