Moderna and Pfizer boosters eyed for J&J shot recipients
People who got the Johnson & Johnson coronavirus vaccine may be better off with a booster shot from Moderna or Pfizer-BioNTech, according to preliminary data from a federal clinical trial published Wednesday.
That finding, along with a mixed review of Johnson & Johnson’s booster data from the Food and Drug Administration released earlier in the day, could lead to a heated debate about whether and how to offer additional shots to the 15 million Americans who have received the single-dose vaccine.
The agency’s panel of vaccine advisers will meet Friday and vote on whether to recommend that the agency authorize the company’s application for boosters for recipients of its vaccine.
Despite these questions about the strength of J&J boosters, some experts anticipated that the agency would clear the shots anyway to meet the public’s demand. Once the agency authorized a booster from Pfizer-BioNTech last month, “the die was cast,” said John Moore, a virus expert at Weill Cornell Medicine.
In a study conducted by the National Institutes of Health, researchers organized nine groups of roughly 50 people. Each group received one of the three authorized vaccines, followed by a booster. In three groups, volunteers received the same vaccine for a boost. In the other six, they switched to a different one.
The researchers found that those who got a Johnson & Johnson shot followed by a Moderna booster saw their antibody levels rise 76fold within 15 days, whereas those who received another dose of Johnson & Johnson saw only a fourfold rise in the same period. A PfizerBioNTech booster raised antibody levels in Johnson & Johnson recipients 35-fold.
Still, the authors cautioned about the study’s small size and noted that they didn’t follow the volunteers long enough to identify potential rare side effects.
The study also was limited in how it measured the immunity provided by boosters. The researchers only looked for antibodies that can stop the coronavirus from replicating in cells. They didn’t examine how well the booster trains immune cells to recognize and kill infected cells.
Earlier Wednesday, an FDA analysis questioned the strength of evidence Johnson & Johnson provided in its application for boosters.
A key test used by the company to measure the immune response of a sixmonth-boost — known as a psVNA assay — wasn’t sensitive enough for the task, the analysis said. The agency also questioned whether the increase in immune response was as big as the data suggested.
“It is likely that the results seen are due to the low sensitivity of the psVNA assay used,” the FDA stated in its report. Regulators also said they didn’t have enough time to independently review much of the raw data from the company’s trials.
The FDA saw a potential improvement in protection from a J&J booster given two months after the first shot, based on a large trial sponsored by the company.
“Although not independently confirmed by FDA from datasets, summaries of the data suggest there may be a benefit in a second dose administered approximately 2 months after the primary dose,” the agency said in its report.
Johnson & Johnson in a statement said it looked forward to discussing the data at the Friday meeting, where panelists also will hear a presentation from the authors of the mix-andmatch study.
The FDA’s discussion this week of the Johnson & Johnson vaccine has big implications for the shot’s future in the U.S., said Jason Schwartz, an associate professor of health policy at the Yale School of Public Health.
The vaccine already was unlikely to have much staying power in the U.S., he said. And if the FDA recommends that Johnson & Johnson recipients get a booster of a different vaccine, “it’s hard to see what would steer people to the J&J vaccine.”