NIH-Backed Study Finds Moderna, Pfizer Boosters Work Best

After months of dithering about the potential safety risks of mixing and matching various approved COVID vaccines, a long-running NIH-sponsored study has found that patients can safely and effectively receive booster shots from any of the major approved vaccines, even as the FDA’s vaccine advisory committee has sounded lukewarm about the prospect of approving booster jabs for all adults over the age of 18.

According to Bloomberg, the complicated 9-arm trial involved over 450 people and measured the effects from giving a booster shot of the Moderna, Pfizer, BioNTech or J&J vaccines to those who had originally gotten a different vaccine. The data showed that the new jabs increased patients’ levels of neutralizing antibodies, sometimes by more than would be expected if they received a third jab of the same vaccine they had received initially.

“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,” the researchers said in their conclusion.

In the abstract from the preprint of the study (which can be found on medrxiv.org) the researchers claimed they were embarking on this research because of the persistent breakthrough infections that continue to occur in some patients. While “homologous” mRNA booster jabs have received approval in some jurisdictions (Israel, and now the EUA, are now allowing some patients to receive a third dose of whatever initial jab they received)

In total, 458 individuals were enrolled: 154 received mRNA-1273 (Moderna), 150 received Ad26.CoV2.S (J&J), and 154 received BNT162b2 (Pfizer) booster vaccines. The study was sponsored and primarily funded by the NIH.

Participants were divided into nine groups with roughly 50 volunteers in each. Those who initially got the two-dose Moderna vaccine got either another Moderna shot, a Pfizer shot or a J&J shot as a booster four to six months after their primary immunization.

People who got the two-dose Pfizer vaccine got either another Pfizer shot or a Moderna or J&J booster. And people who got the one-shot J&J vaccine, either got another J&J shot, or a Moderna or Pfizer booster. Antibody levels were then measured at two weeks and four weeks after the booster dose.

Data showed that homologous boosters increased neutralizing antibodies by 4.2-20-fold while heterologous boosters created an increase of 6.2-76-fold. The conclusion: Conclusion: “Homologous and heterologous booster vaccinations were well-tolerated and immunogenic in adults who completed a primary Covid-19 vaccine regimen at least 12 weeks earlier.”

Notably, the study found that for patients who initially received the J&J jab, switching to an mRNA jab (Pfizer’s or Moderna’) for the booster dose might afford them better protection. Regardless of the initial jab, Pfizer and Moderna boosters appeared to work best.

More detail about the study are expected Friday afternoon during a meeting of an FDA advisory panel, where researchers conducting the trial are scheduled to give a presentation on their early findings. A panel will also meet Thursday to deliberate over Moderna’s application for booster-jab approval.

Find the full pre-print below:

2021.10.10.21264827v1.full by Joseph Adinolfi Jr. on Scribd