The Johnson & Johnson vaccine works best as a two-dose regimen — and a second shot should now be offered to anyone who got their first dose more than two months ago, according to a Friday vote by a U.S. Food and Drug Administration panel.
But new results from a federal trial show that a potentially better strategy is on the horizon: switching vaccines to boost immunity, where J&J recipients are offered access to either the Pfizer or Moderna vaccine.
That leaves J&J recipients in booster-shot limbo. Citing insufficient time to review new data, the FDA panel did not vote Friday on a vaccine-mixing approach but said it will likely discuss in the future.
When first introduced, J&J’s one-dose vaccine was pitched as a game-changer. Simple to administer, it doesn’t demand cold storage. It’s convenient for rural or hard-to-reach populations who don’t want to return for a second shot.
But its effectiveness has been consistently lower than Pfizer and Moderna’s mRNA vaccines.
This has been anxiety-inducing for the 14 million Americans who got the J&J vaccine. Even as others rushed out for third shots of the Pfizer and Moderna vaccines, they were left behind.
“This is a group that overall sees lower efficacy than the mRNA vaccines, so there is some urgency to the matter,” said epidemiologist Dr. Arnold Monto of the University of Michigan, chair of the FDA panel.
J&J delivered long-awaited news at the meeting, announcing that immunity — measured by antibody levels — jumps when a second dose is given two months after the first. According to the company’s 30,000-patient study, the second shot boosted the vaccine’s ability to prevent infection from 74% to an impressive 94%. There was no increase in side effects.
“It’s what many of us have advocated for months,” tweeted Dr. Céline Gounder, an infectious disease specialist at the New York University Grossman School of Medicine.
Anyone who got the J&J vaccine should be eligible, according the panel’s unanimous vote. In contrast, the Pfizer and Moderna boosters are more restricted, recommended only for people who are at highest risk of serious COVID-19 disease because of their age, underlying health conditions or high risk of viral exposure where they work or live.
“If the vaccine isn’t adequate, then it should be boosted in everybody,” said immunologist Dr. Eric Rubin of Harvard’s School of Public Health and editor-in-chief of The New England Journal of Medicine
The next step is to get the go-ahead from FDA acting Commissioner Dr. Janet Woodcock and U.S. Centers for Disease Control and Prevention. The CDC is slated to meet next week.
But the panel deferred a decision on a much more consequential and complicated policy shift: switching vaccines midstream.
A new study by the National Institutes of Health shows that a one-two punch using different vaccines can be as potent as either vaccine alone — and may, in fact, be better.
Antibodies increased in response to any boost, regardless of the type of initial vaccine, according to a national study of about 460 Americans presented by Dr. Kirsten Lyke of the University of Maryland School of Medicine.
If J&J recipients got a J&J boost, their antibody levels rose 4.2-fold, according to the study. But if they instead got the Pfizer vaccine, levels jumped 33-fold. A Moderna boost triggered a significant 56-fold increase.
This research, dubbed the “MixNMatch” study, does not yet have data about the response from the other important arm of the immune system, involving memory B cells and T cells. That will be available in November, said Lyke.
Already, many aren’t waiting around for federal health authorities to give the green light. On social media, those who had J&J’s shot trade advice on whether and how to top it off with a Pfizer or Moderna jab for extra protection.
Mixing the two types of vaccine, which use different approaches, may give the immune system multiple ways to recognize a pathogen, the journal Science reported on June 9.
The J&J vaccine enlists a harmless virus, called an adenovirus, to carry the DNA code for the virus’s spike protein. In contrast, the Pfizer and Moderna vaccines use messenger RNA code, which the cells use to make the protein.
More data is needed to prove that a mix and match combination is better at fending off infection, illness and hospitalization, the panel agreed. And it’s too early to say if its immunity is more long-lasting.
And before such an approach could be adopted, it may be necessary to change the language of the FDA’s “emergency use authorizations” for the vaccines, said Dr. Steven Pergram of Seattle’s Fred Hutchinson Cancer Research Center.
But there is comfort in knowing that the vaccines are safe and well understood, said Rubin.
With at least 16 vaccines approved for use around the world, a mixing strategy could reduce the risk of sudden supply problems and accelerate global protection. Already, Canada and several European countries recommend a different vaccine for the second dose for some patients.
Will the FDA consider a recommendation to mix-and-match?
“I would say it’s possible,” said Dr. Peter Marks, the head of the FDA’s Center for Biologics Evaluation and Research, which approves vaccines.
Source: www.mercurynews.com