their boosters; one had received Moderna and the other J&J. Two other people who got a J&J booster reported fatigue or insomnia.
Scott Hensley, an immunologist at the University of Pennsylvania, tells the Times that the results are compelling. He notes, however, that the trial only looked at antibody levels, which aren’t the sole measure of an immune system response.
Should you mix and match?
“At the end of the day, folks having the Johnson & Johnson should probably get an mRNA booster,” he says. “It’s just a matter of how much data does the FDA need before making that recommendation? I wouldn’t want to be in their shoes.”
E. John Wherry, director of the Institute for Immunization at the University of Pennsylvania, says the findings suggest that boosters of the Pfizer or Moderna vaccines would be best for people who received the J&J vaccine. But the lower antibody levels measured after the J&J booster shot do not necessarily equal worse protection, he adds.
“I don’t think this is the end of the story,” he tells NBC News. “I think this is the beginning of the discussion.”
Wherry adds that the most important finding was that it is safe to mix different vaccines and boosters. Further studies will be able to provide more details about the performances of different combinations, he shares.
How efficient are the booster shots?
The FDA has already authorized an additional shot of the Pfizer vaccine for Americans over 65, or those 18 to 65 with underlying health conditions or jobs that put them at higher risk. Moderna’s booster shot application, which will be discussed on Thursday, may also win authorization even though only limited evidence suggests the power of the two-shot vaccine is waning.
Unlike Pfizer’s and Moderna’s two-shot vaccines, J&J had hoped to offer a one-shot solution to the pandemic. But its protection, at 72% in the United States, is not as robust as Moderna’s and Pfizer’s vaccines, which have both touted efficacy rates well above 90%, CNBC reports.
However, a second dose of J&J’s shot does boost protection from symptomatic infection to 94% when administered two months after the first dose in the United States, according to company data released in September.
In a separate document published on Wednesday, the FDA said data provided by J&J suggests recipients may benefit from an additional dose given two months after the initial shot.