The National Institutes of Health study on “mixing and matching” COVID vaccines included more than 450 adults who have received one of the three regimens currently available in the United States: J&J’s, Moderna’s, or Pfizer’s. The study, which looks at whether there are any advantages or drawbacks to using different boosters, hasn’t yet been peer-reviewed.
Among people who originally received a J&J shot, antibody levels were four times higher after a J&J booster, 35 times higher after a Pfizer booster, and 76 times higher after a Moderna booster.
The study also found that Moderna recipients had higher antibody levels “irrespective of the booster vaccine administered,” when compared with those who had initially been inoculated with the Pfizer or J&J vaccine.
Researchers wrote in the study, “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. Heterologous prime-boost strategies may offer immunological advantages to optimize the breadth and longevity of protection achieved with currently available vaccines.”
In a separate document published, the FDA said data provided by J&J suggests recipients may benefit from an additional dose given two months after the initial shot.
Regulators wrote that estimates on the effectiveness of J&J’s single-shot vaccine in trials and real-world studies “are consistently less than the highest effectiveness estimates for the mRNA COVID-19 vaccines.”