J&J Covid vaccine recipients are better off getting Pfizer or Moderna booster, NIH study suggests

Pfizer-BioNTech Covid-19 vaccines at a senior living facility in Worcester, Pennsylvania, U.S., on Wednesday, Aug. 25, 2021.Hannah Beier | Bloomberg | Getty Images

Johnson & Johnson Covid-19 vaccine recipients are better off getting a booster shot from Pfizer or Moderna, a highly anticipated U.S. study suggested Wednesday.

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 hasn't yet been peer-reviewed.

Volunteers were divided into groups and received an extra shot of their original vaccine or a booster from a different company. Antibody levels were measured two weeks and four weeks after the boosters were given.

All the combinations boosted antibody levels higher, though Pfizer's and Moderna's boosters appeared to work best. People who received a booster dose of either the Moderna or Pfizer vaccines had a four-fold increase in their antibody responses more often than those who received an extra dose of J&J, according to the study.

The study showed recipients of Moderna or Pfizer's original vaccines could easily swap third doses; the results were about the same. Volunteers who originally received the J&J vaccine appear to have gotten a better immune response if they got a booster made by Pfizer or Moderna.

"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," researchers wrote in the study. "Heterologous prime boost strategies may offer immunological advantages to optimize the breadth and longevity of protection achieved with currently available vaccines," they added.

J&J's one-dose vaccine uses an adenovirus, while Pfizer's and Moderna's two-dose vaccines use mRNA technology. The thought by some scientists is is that by "mixing and matching" vaccines that use different platforms, people may be able to get broader protection against the coronavirus and its new variants.

The findings published Wednesday are expected to be presented at a key Food and Drug Administration vaccine advisory committee meeting on Friday.

This is a developing story. Please check back for updates.

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