COVID-19 Cases and Deaths by Vaccination Status

Background

To determine the effects of vaccination on COVID-19 cases and deaths in Texas, researchers at the Texas Department of State Health Services analyzed data from electronic lab reports, death certificates, and the state immunization registry. By comparing COVID-19 case and death rates among people who were unvaccinated to those who were fully vaccinated, DSHS was able to calculate the impact of vaccination in Texas.

The analysis included a period from Jan. 15 to Oct. 1 with a particular focus on the four weeks from Sept. 4 to Oct. 1, which allowed the agency to measure the effect of COVID-19 vaccination as the more contagious Delta variant surged across Texas.

All authorized COVID-19 vaccines in the United States are highly effective at protecting people from getting sick or severely ill with COVID-19, including those infected with Delta and other known variants. Real world data from Texas clearly shows these benefits. A summary of the data is included on this page, and the full report is also available for download.


Key Findings

  1. From September 4 through October 1, 2021:
    • Unvaccinated people were 13 times more likely to become infected with COVID-19 than fully vaccinated people.
    • Unvaccinated people were 20 times more likely to experience COVID-19-associated death than fully vaccinated people.
  2. Vaccination had a strong protective effect on infections and deaths among people of all ages. The protective impact on infections was consistent across adult age groups and even greater in people ages 12 to 17 years. The protective impact on COVID-19 deaths, which was high for all age groups, varied more widely. In the September time frame, unvaccinated people in their 40s were 55 times more likely to die from COVID-19 compared with fully vaccinated people of the same age. Unvaccinated people aged 75 years and older were 12 times more likely to die than their vaccinated counterparts.
  3. Overall, regardless of vaccination status, people in Texas were four to five times more likely to become infected with COVID-19 or suffer a COVID-19-associated death while the Delta variant was prevalent in Texas (August 2021) compared with a period before the Delta variant became prevalent (April 2021).

Overall crude case rate (daily 7-day moving average) by vaccination status from Jan. 15, 2021 to Oct. 1, 2021

Line chart of Overall crude case rate (daily 7-day moving average) by vaccination status from January 15, 2021 to October 1, 2021. Download PDF file at top of page for complete data.

  • From Jan. 15 to Oct. 1, unvaccinated people were 45 times more likely to have an infection with COVID-19 than fully vaccinated people.
  • From Sept. 4 to Oct. 1, unvaccinated people were 13 times more likely to become infected than fully vaccinated people.
  • For both periods, the impact was strong across all age groups with the greatest protective effect in children 12 to 17 years of age.


Overall crude death rate (daily 7-day moving average) by vaccination status from Jan. 15, 2021 to Oct. 1, 2021

Line chart of Overall crude death rate (daily 7-day moving average) by vaccination status from January 15, 2021 to October 1, 2021. Download PDF file at top of page for complete data.

  • From Jan. 15, 2021 to Oct. 1, 2021, unvaccinated people were 40 times more likely to experience COVID-19-associated death than fully vaccinated people.
  • From Sept. 4, 2021 to Oct. 1, 2021, unvaccinated people were 20 times more likely to experience COVID-19-associated death than fully vaccinated people.
  • For both periods, the impact was strong across all age groups with a somewhat smaller protective effect in older adults at least 75 years old.


Data Sources and Time Frame

Data sources:

  • ImmTrac2, Texas Immunization Registry
  • Death Registry, Vital Statistics
  • COVID-19 ELR, National Electronic Disease Surveillance System Electronic Laboratory Reporting

The rates presented in this report were calculated using the state population distribution based on the 2019 U.S. Census standard population estimates. Calculations include only the 12 and older population because they are eligible to be vaccinated. The analysis timeframe was chosen because Jan. 15, 2021 represents the first day a Texan could be fully vaccinated, and Oct. 1, 2021 represents the most recent date with complete available data.


Limitations

  • Duplicates among exact matches were hand checked. Those who had outliers such as a vaccine dose date after a date of death were classified as unvaccinated. However variable linkage of case, vaccination, and mortality data might have resulted in misclassifications that could influence IRR estimates.
  • ELR data and death registry are updated on an ongoing basis, lags in reporting may have led to some information being incomplete at the time of analysis.
  • Immunization data for COVID-19 are dependent on clinician report of status to ImmTrac2.

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Last updated November 15, 2021