People who receive a COVID-19 booster that's a different brand than their primary vaccine series may be better protected against COVID-19, according to a study from Singapore published Feb. 11 in the Journal of the American Medical Association.
Using national data from the Singapore Ministry of Health, researchers analyzed the incidence and severity of COVID-19 cases between Sept. 15 and Oct. 31, 2021, among people 60 and older eligible to receive booster shots. Of more than 703,000 eligible people, 576,132 received Pfizer or Moderna boosters.
People who got the Pfizer vaccine for their primary series and booster had a COVID-19 incidence rate of 227.9 per million person-days, compared to 147.9 for people who received Pfizer for the primary series and Moderna for the booster. Among those who had Moderna shots for their primary series, the infection incidence rate was 133.9 cases per million person-years with a Moderna booster and 100.6 per million person-days with a Pfizer booster.
Overall, people who got a booster had lower rates of severe COVID-19 than people who did not.
"The study results support recommendations for vaccine boosters and suggest that heterologous boosting may provide greater protection against COVID-19," researchers concluded.
View the full study here.