In a new analysis, the Food and Drug Administration questioned the strength of evidence Johnson & Johnson provided in its application for booster shots. A key test used by the company was likely not sensitive enough, the agency suggested, adding that it didn’t have enough time to independently review much of the raw data from the trials.
The document, released in advance of a Friday meeting of the agency’s vaccine advisers, could have significant influence on whether the 15 million Americans who have received the one-dose vaccine will be allowed to get a second shot, or if they will instead be urged to get a different brand of vaccine for added protection.
The agency’s analysis follows a report released on Tuesday, in which Johnson & Johnson argued in favor of a booster, presenting data from a number of trials.
“A booster dose is recommended at 6 months or later, based on the strength of the immune responses,” the company wrote.
But on Wednesday, the F.D.A. said that the test used by the company to measure the immune response of a six-month-boost — known as a psVNA assay — is not sensitive enough for the task. 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 F.D.A. stated in its report.
The F.D.A. 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 F.D.A. 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.
The fact that the F.D.A. had not independently confirmed key data was a departure from past briefing documents for other vaccines. The F.D.A. said that it didn’t have time to vet much of Johnson & Johnson’s material before the meeting later in the week.
The agency scheduled the meeting of its outside advisers before the company had even submitted its application for a booster dose — an unusual move, some public health experts said.
“Except where noted, datasets were not submitted in sufficient time for FDA to conduct an independent review to verify the Sponsor’s analyses,” the F.D.A. said in its report.
A spokesman for Johnson & Johnson did not immediately respond to a request for comment.
The F.D.A. has already authorized an additional shot of the Pfizer-BioNTech vaccine for people over 65 years of age, or with health conditions or job exposures that put them at higher risk. Moderna has also submitted an application for a booster which will be evaluated by the F.D.A.’s advisers on Thursday. It may also win authorization, despite limited evidence that the protection provided by an initial two doses of Moderna is waning.
When Johnson & Johnson’s vaccine was authorized in February, it had several advantages over the other two. As a single shot, it was more convenient than the two-dose formulation from Moderna and Pfizer-BioNTech. It also didn’t have to be frozen to stay viable. But it also provided less robust protection.
What to Know About Covid-19 Booster Shots
The F.D.A. authorized booster shots for a select group of people who received their second doses of the Pfizer-BioNTech vaccine at least six months ago. That group includes: Pfizer recipients who are 65 or older or who live in long-term care facilities; adults who are at high risk of severe Covid-19 because of an underlying medical condition; health care workers and others whose jobs put them at risk. People with weakened immune systems are eligible for a third dose of either Pfizer or Moderna four weeks after the second shot.
The C.D.C. has said the conditions that qualify a person for a booster shot include: hypertension and heart disease; diabetes or obesity; cancer or blood disorders; weakened immune system; chronic lung, kidney or liver disease; dementia and certain disabilities. Pregnant women and current and former smokers are also eligible.
The F.D.A. authorized boosters for workers whose jobs put them at high risk of exposure to potentially infectious people. The C.D.C. says that group includes: emergency medical workers; education workers; food and agriculture workers; manufacturing workers; corrections workers; U.S. Postal Service workers; public transit workers; grocery store workers.
It is not recommended. For now, Pfizer vaccine recipients are advised to get a Pfizer booster shot, and Moderna and Johnson & Johnson recipients should wait until booster doses from those manufacturers are approved.
Yes. The C.D.C. says the Covid vaccine may be administered without regard to the timing of other vaccines, and many pharmacy sites are allowing people to schedule a flu shot at the same time as a booster dose.
A clinical trial showed that one dose of J. &. J. had an efficacy rate of 66 percent against moderate to severe Covid-19 worldwide, and 74 percent in the United States. Its efficacy against either severe or critical disease was stronger, at 85 percent worldwide.
In its application for a booster, Johnson & Johnson included the results of another large-scale trial that began in November, in which they gave half their volunteers a second dose two months after the first. The other half received a placebo.
In August, the company announced that in the portion of the trial that took place in the United States, the efficacy rose to 94 percent. But in its report, the F.D.A. focused on the worldwide results, in which the increase more modest, rising to 75 percent.
Against severe to critical Covid-19, two shots had an efficacy of 100 percent. But regulators warned in the analysis posted Wednesday that there was little data from that trial on the Delta variant, which now causes the vast majority of infections in the United States.
“The small number of accrued cases confirmed to be caused by the Delta variant precludes any conclusion regarding efficacy against that variant,” they wrote.