The National Institutes of Health (NIH), in a study, found that booster shots can be safely and effectively mixed with COVID-19 vaccines. However, the Centers for Disease Control and Prevention still recommends against mixing vaccines.
The “Mix and Match Study” was published Wednesday on medRxiv.orgIt has not been peer-reviewed.
More than 450 people received a COVID-19 regimen from Johnson & Johnson or Moderna.
Participants were then divided into groups, and each group received either an additional shot of the original vaccine or a booster from another company. The antibody levels of the participants were tested two weeks and then four weeks later.
Researchers discovered that J&J vaccine recipients were more likely to have stronger antibodies than those who had received booster shots from Moderna or Pfizer.
Study results showed that people who had received Moderna shots or Pfizer vaccines as well as booster shots from either company produced similar immune responses.
“These data suggest that if a vaccine is approved or authorized as a booster, an immune response will be generated regardless of the primary COVID-19 vaccination regimen,” wrote the researchers.
According to the researchers, participants responded to the second round of shots in a similar way to they did to the first series.
“Injection site pain, malaise, headache, and myalgia occurred in more than half the participants,” they wrote.
The researchers concluded that homologous and heterologous booster shots were well-tolerated in adults who had received at least 12 weeks prior a primary COVID-19 regimen.
NBC News reports that the findings of this study will be presented to the Food and Drug Administration (FDA) advisory committee on Friday, when they’ll be meeting to consider recommending the authorization of booster shots for the Moderna and J&J vaccines.
The only booster shot approved so far in the U.S. is Pfizer’s and it’s only available for certain groups. At this time, the CDC says the authorization only applies to people whose primary series was with Pfizer’s vaccine.
“People in the recommended groups who got the Moderna or J&J/Janssen vaccine may need a booster shot,” wrote the CDC. “More data on the effectiveness and safety of Moderna and J&J/Janssen booster shots are expected soon. With those data in hand, CDC will keep the public informed with a timely plan for Moderna and J&J/Janssen booster shots.”