Department of Research & Evaluation News

COVID-19 vaccine recipients had lower non-COVID-19 death rates than people who weren’t vaccinated, according to Kaiser Permanente research published Oct. 22, 2021 in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report.

“Despite numerous studies showing the safety of COVID-19 vaccines, some people have remained hesitant to get vaccinated,” said lead author Stanley Xu, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation. “This study provides reassurance that the vaccines are very safe, and, in fact, people who received COVID-19 vaccines in the United States had a lower death rate than those who didn’t, even if you don’t count COVID deaths.”

To determine mortality risk associated with COVID-19 vaccination, researchers evaluated the electronic health records of 6.4 million COVID-19 vaccine recipients compared to 4.6 million unvaccinated people with similar demographics and geographic locations from December 14, 2020, through July 31, 2021. The study looked at only non-COVID-19-related deaths to avoid masking any safety concerns regarding COVID-19 vaccine-related death with the protective effects of COVID-19 vaccine.

The study population included members of 7 Vaccine Safety Datalink sites: Kaiser Permanente Southern California, Kaiser Permanente Northern California, Kaiser Permanente Colorado, Kaiser Permanente Northwest, Kaiser Permanente Washington, HealthPartners in Minnesota, and Marshfield Clinic in Wisconsin.

The Pfizer and Moderna mRNA vaccines require 2 doses for full vaccination, while the Johnson & Johnson adenoviral vector vaccine requires only one dose. The 1-dose and 2-dose vaccines had different comparison groups due to differences in when the vaccines were available and potential differences in the demographics of people who chose the 1- or 2-dose vaccines. All analyses were adjusted for age, sex, race, ethnicity, and Vaccine Safety Datalink site.

• Pfizer COVID-19 vaccine recipients had a mortality rate of 4.2 deaths per 1,000 vaccinated people per year after first dose, and 3.5 deaths after second dose.
  • The unvaccinated comparison group had a mortality rate of 11.1 deaths per 1,000 people per year.
• Moderna COVID-19 vaccine recipients had 3.7 deaths per 1,000 people per year after the first dose, and 3.4 deaths after the second dose.
  • The unvaccinated comparison group had a mortality rate of 11.1 deaths per 1,000 people per year.
• Johnson & Johnson COVID-19 vaccine recipients had 8.4 deaths per 1,000 people per year.
  • The unvaccinated comparison group had a mortality rate of 14.7 deaths per 1,000 people per year.

This study was funded through the Vaccine Safety Datalink under a contract from the Centers for Disease Control and Prevention. The Vaccine Safety Datalink was established more than 30 years ago and includes approximately 3% of the U.S. population. Each participating site regularly prepares standardized data files containing information on demographics, health plan enrollment, births, vaccinations, mortality, and health care utilization. With computerized and standardized data, researchers have been able to combine data from multiple sites and conduct large observational vaccine safety studies while maintaining member confidentiality.

In addition to Dr. Xu, other authors on the study were Runxin Huang, MS; Lina S. Sy, MPH; Sungching Glenn, MS; Denison S. Ryan, MPH; Kerresa Morrissette, MPH; Hung Fu Tseng, PhD; and (senior author) Lei Qian, PhD, of Kaiser Permanente Southern California Department of Research & Evaluation; David K. Shay, MD, of the Centers for Disease Control and Prevention COVID-19 Response Team; Gabriela Vazquez-Benitez, PhD, of HealthPartners Institute, Minneapolis, Minnesota; Jason M. Glanz, PhD, of the Kaiser Permanente Institute for Health Research, Denver, Colorado; Nicola P. Klein, MD, PhD, of the Kaiser Permanente Vaccine Study Center, Kaiser Permanente Northern California, Oakland, California; David McClure, PhD, of the Marshfield Clinic Research Institute, Marshfield, Wisconsin; Elizabeth G. Liles, MD, of the Kaiser Permanente Northwest Center for Health Research, Portland, Oregon; and Eric S. Weintraub, MPH, of the Immunization Safety Office, Centers for Disease Control and Prevention, Atlanta, Georgia.