The idea of mixing and matching different COVID-19 vaccines is gaining momentum, with a special focus on letting Johnson & Johnson vaccine recipients get a dose produced by a different company.
The J&J shot produces inferior results compared to the vaccines that were created using messenger RNA technology, according to studies and real-world evidence. The main reason to allow heterologous vaccination schedules would be the aim of giving people who got a J&J vaccine to get a boost in protection.
“I think what needs to be done—and I believe will be done—is that there will be a degree of flexibility that will be left up to the individual based on their individual situation,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on “Fox News Sunday.”
Scientists with Fauci’s agency and other institutions have been studying whether mixing and matching vaccines provokes immune system responses and is safe.
They presented interim findings on a phase 1/2 study to members of the Food and Drug Administration’s (FDA) vaccine advisory panel on Oct. 15.
Researchers found (pdf) that the best results were among J&J recipients who got a dose of the Moderna or Pfizer vaccine, which are both based on mRNA technology.
The panel wasn’t asked to vote on whether to allow mixing and matching of vaccines, but several members said they would have backed the move if they had voted, even though the sample size from the study, which is not yet complete, is small.
“I’m sold already,” said Dr. Mark Sawyer, professor of clinical pediatrics at the University of California–San Diego. “We need flexibility and improved access for everybody, which the flexibility of being able to mix and match will allow.”
Letting recipients who are at elevated risk of serious side effects—middle-aged women are at higher risk of getting blood clotting with low blood platelet levels from J&J’s shot, while young males are at higher risk of heart inflammation from the mRNA vaccines—switch to a different jab for later doses makes sense from a public health perspective, said Dr. Amanda Cohn, a top medical officer at the Centers for Disease Control and Prevention.
Other members said the immunogenicity data, which showed a boost of neutralizing titers, was impressive but said there’s no clear data linking the titers to protection against the CCP virus, which causes COVID-19.
There are other concerns, including how vaccine mixing would affect cellular immunity.
“It would be, I think, critically important to see what happens to the cellular immunity as well as we try to do this heterologous boosting,” said Dr. Archana Chatterjee, dean of the Chicago Medical School.
The FDA hasn’t set a timeline for asking the panel for formal advice on mixing. The panel last week recommended that the agency expand who can get boosters for the Moderna and Johnson & Johnson vaccines, following a similar recommendation for Pfizer’s shot.
But some panel members urged the FDA to move quickly, noting that tens of thousands of Americans are already mixing vaccines.
San Francisco’s Public Health Director Grant Colfax announced over the summer that city residents who get the single-shot J&J vaccine would be able to get a Pfizer or Moderna booster.
Everybody who got a J&J shot should get a boost, said Dr. Tom Russo, professor and chief of infectious disease at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences, pointing to data showing that the Moderna and Pfizer vaccines are more effective against symptomatic infection and severe disease.
“Their shields are down to the greatest degree, so to speak,” he told The Epoch Times. “And I hate to see them put in a quandary, ‘Well you could get a second J&J shot now, or you can wait and see if they approve that mRNA vaccine as a booster.’ It sort of puts them a little bit in limbo right now.”