“If and when FDA and CDC approve a change in policy, then it looks to me entirely appropriate to consider using the mRNAs as a boost for J&J,” said Moore.
In a statement, the FDA said that J&J remains a single-dose shot and that no data is available yet on its interchangeability with other covid vaccines. The CDC said the agency is continuing “to monitor and evaluate COVID-19 vaccine effectiveness.”
Diemert said the data from J&J’s studies supports his view that at this time a booster shot isn’t necessary for those who got J&J.
“Now that we have data that is encouraging that the vaccine might be protective against delta and that the duration of protection is a thing, those two together are encouraging that a booster might not be needed,” said Diemert.
Dr. Robert Wachter, chair of the Department of Medicine at the University of California-San Francisco, said he doesn’t think an mRNA booster is necessary either — but he would still caution those who got J&J to be a bit more careful than those who received Pfizer-BioNTech or Moderna.
“The main difference would be definitely masking indoors (unless certain that everybody was vaccinated), whereas for mRNA vax recipient, I see that as more elective,” Wachter wrote in an email.
As for those who got J&J and have already gotten an mRNA booster shot? For some, the new findings come as a relief.
“These results are great news. I don’t find them surprising, but they are some of the data that was missing when I decided to take an mRNA booster,” said Jason Gallagher, a clinical pharmacy specialist in infectious diseases at Temple University Hospital in Philadelphia.
He got a dose of the Pfizer-BioNTech vaccine after receiving the J&J vaccine because he was concerned about a U.K. study that indicated one dose of the Oxford-AstraZeneca or Pfizer-BioNTech vaccine was much less effective against the delta variant than two doses.
Gallagher said he might not have gotten a booster if the J&J results had been available a month ago, but he doesn’t regret his decision.
“This is an immunologic study suggesting that the vaccine will work against the delta variant, not a clinical study describing whether it did. I’m looking forward to learning more about that,” said Gallagher.
For those who are still considering getting an mRNA booster, it’s important to know that vaccine sites may ask whether you have already been vaccinated against covid. These sites have been instructed to administer vaccines according to CDC and FDA guidelines and have not been authorized to give additional shots to those who have already received a complete vaccine regimen.
Experts also emphasized that the best way to protect against the highly transmissible delta variant is to achieve a high vaccination rate across the U.S. When more people are vaccinated, the amount of circulating virus is reduced, which means everyone is better protected, including those who got the J&J shot.
Almost 67% of U.S. adults have received at least one vaccine dose, but only 47% of the total population is fully vaccinated. Rates of vaccination also vary widely by state. In other words, location has a lot to do with risk. Several Southeastern and Midwestern states, for instance, have less than 55% of their population vaccinated, meaning the delta variant could more easily sweep through those areas.
“All of the evidence on our currently authorized vaccines in the U.S. suggests they remain highly effective against preventing severe disease even against the variants,” said Dr. William Moss, executive director of the International Vaccine Access Center at Johns Hopkins University in Baltimore.