Study finds that mixing COVID vaccines produces as many antibodies as the same shot booster, even if it takes more than one shot
According to preliminary results of a long-awaited government-funded trial, mixing COVID-19 vaccines produces as many or more antibodies as using the same shot as reactivator.
The trial is the first major U.S. study to compare the effects of using different vaccines as boosters from the initial shot or shots. The lengthy, 9-arm trial involved over 450 individuals and measured the effects of giving a booster shot of the Moderna Inc., Pfizer Inc-BioNTech SE, or Johnson & Johnson vaccines to those who had previously received fewer vaccine injections.
Overall, the researchers stated in the preprint on medRxiv.org that mixing-and-matching resulted in comparable or higher levels of neutralizing antibodies compared to same-vaccine boosting. The study concluded that the rates of adverse events were similar across all the different booster groups.
These data suggest that if a vaccine is approved or authorized as reactivator, an immune response will be produced regardless of the primary COVID-19 vaccination regimen, the researchers wrote in their conclusion.
The results of the ongoing study have not yet been peer reviewed or published in a medical journal. More information about the study is expected to be revealed Friday afternoon at a meeting of the FDA advisory panel, where researchers conducting the trial are expected present their early findings.
Mixing and matching boosters have become a more frequent concern. Many countries outside of the United States have adopted the technique in an attempt to increase vaccine effectiveness or avoid the few side effects that have been associated with some shots.
As a booster, some people who received the Johnson & Johnson shot may be interested in getting RNA messenger shots in the United States. Mix-and-matching may also make it simpler for officials to distribute boosters more broadly, as individuals getting booster shots may have any COVID-19 vaccine on hand at their pharmacy and wouldnt have to look for the shot they had previously received.
Outside of the United States, fears about rare blood clots associated with AstraZeneca Plcs vaccine prompted many countries in Europe to halt use of it and instead prescribe a different second dose. In the United Kingdom, health authorities have begun a booster program that provides an extra dose of the Pfizer vaccine as the preferred choice, as well as delivering saturday's Moderna shot.
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