The official guidance about booster shots has largely left out 14 million people: Those who got the Johnson & Johnson vaccine. With a new announcement from the company, that could change.
The discussion about boosters has so far centered on the mRNA vaccines—and it’s involved a lot of confusing back-and-forth. Last month, President Joe Biden announced the plan to offer additional shots for adults who received the Pfizer or Moderna vaccines starting Sept. 20. But on Wednesday, the Food and Drug Administration authorized Pfizer vaccine boosters only for those 65 and older and others at high risk of getting severe COVID. The discussion of Moderna booster shots for all adults is still ongoing, as health regulators requested more time to review the data submitted by the company. In the meantime, immunocompromised people can already get Moderna or Pfizer booster shots, according to recommendation officials issued last month.
But, until recently, there’s been nothing official at all about boosters for the J&J vaccine, which comes in a single dose and offers less protection that the other options. There hasn’t even been guidance on what immunocompromised people who got the single-dose vaccine should do in terms of an additional shot. Experts have for months been advising people who receive the J&J vaccine and are interested in getting a booster that it might be a good idea—but that they should consult their physician, who in turn may or may not be comfortable giving advice about coronavirus booster vaccines. Those who did decide to get a booster (perhaps mixing and matching J&J with an mRNA shot) sometimes had to skirt the rules to find a place that would give it to them.
There might be better guidance coming soon. Finally, on Tuesday, J&J shared its findings on the effect of booster shots for its vaccine. The company unveiled in a press release that giving a second dose of the vaccine two months after the first shot provides 94 percent protection against moderate or severe COVID symptoms and 100 percent protection against severe-to-critical symptoms. If the second shot is given six months after the first one, the protection is even higher, said the company. Johnson & Johnson didn’t mention the percentage of efficacy in the delayed-booster case, but it did lay things out in terms of antibodies. People who got a booster shot two months after vaccination had antibody levels four to six times higher than after the single shot. Those who received the second dose at six months saw that their antibody levels rose 12 times higher.
These numbers might look like getting two doses of J&J is on par with getting two doses of other vaccines, but the company claims that the data actually indicate something better. When the FDA authorized the Johnson & Johnson vaccine for emergency use in February, its overall efficacy rate in the U.S. was 72 percent, while Moderna and Pfizer effectiveness was around 95 percent. But studies demonstrated that Moderna and Pfizer vaccines’ protection wanes within months. Pfizer effectiveness declines to 84 percent over six months after full vaccination, and Moderna efficacy wanes by 36 percent after 12 months. Johnson & Johnson, however, claims in its press release that its vaccine protection doesn’t weaken over time.
Of course, it’s not clear whether the J&J’s two-dose version of their vaccine will be as compelling once it gets more scrutiny. Some experts were disappointed that Johnson & Johnson published their studies in a press release, as they expected a publication in a scientific journal, where they would be able to see more of the data, and better understand if J&J’s claims hold up. The company promised to submit the results of its trials for publication “in the coming months.” In the meantime, the drugmaker said that it provided data on boosters to the FDA. On Sunday, Anthony Fauci, chief medical adviser to the White House COVID response, told NBC News that the FDA might review data on the second shot for the Johnston & Johnson and third shot for the Moderna in “a couple to a few weeks.”
In the meantime, based on the information J&J did release, it looks like the effectiveness of two shots of the Johnson & Johnson vaccine is comparable to the efficacy of full vaccination with Pfizer or Moderna, which made some wonder: Why wasn’t J&J a two-dose vaccine from the very beginning?
Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.