Five Things to Watch as J&J Covid Vaccine Gets CDC Panel Review

Vaccine experts will meet Friday to review Johnson & Johnson’s Covid-19 shot, which has been on hold for 10 days after several cases of rare and serious blood clots.

The panel of experts, called the Advisory Committee on Immunization Practices, advises the Centers for Disease Control and Prevention. Its 15 voting members will review the evidence and debate whether J&J’s shot should again be used in the U.S., perhaps with new warnings or restrictions, after federal health officials urged pausing use of the shot.

Five Things to Watch as J&J Covid Vaccine Gets CDC Panel Review

Here’s what to watch for during Friday’s meeting, scheduled to run from 11 a.m. to 5 p.m., Eastern.

1. How many cases have emerged?

There were six known reports of the side effect among roughly 7 million shots given as of last week’s meeting, putting the risk of the clotting side effect at about one in a million. The latest number will help the committee evaluate just how common this adverse reaction is, a calculation that will be crucial to the panel deciding whether the benefits of the vaccine outweigh the risks.

Panelists last week wanted to see if more cases of the syndrome, a distinct combination of blood clots and low platelets, would emerge during the pause. About half of the nearly 8 million J&J shots administered in the U.S. were given within the past few weeks, meaning more reports could turn up, especially with so much attention on the syndrome.

2. Do we have a clearer picture of who is at risk?

All six cases of the syndrome were seen among women between the ages of 18 and 48. However, there were so few cases that panelists weren’t comfortable definitively saying women and/or young people are at greatest risk of developing the clots.

In addition, a young man in J&J’s clinical trial developed the blood clot. And in Europe, similar cases of clots linked to AstraZeneca Plc’s Covid-19 vaccine have been seen in both men and women, muddying the picture even more. That vaccine hasn’t been authorized in the U.S. Both the J&J and AstraZeneca shots make use of a cold virus, called an adenovirus, that some scientists have theorized may be linked to clots.

3. Will the advisers recommend restarting use of the vaccine?

This is the main question of the day. The committee has had more than a week to digest the information presented at last week’s meeting, which was held a day after the pause was announced. At least some of the voting members want to resume use of J&J’s shot.

The company’s vaccine is a key tool in the U.S. immunization campaign. It’s a pretty small piece of the U.S. supply, but a popular choice for people and providers since it only requires one shot and can be stored more easily than the vaccines from Moderna Inc. and partners Pfizer Inc. and BioNTech SE. It’s also favored for hard-to-reach populations like the homeless and people who live in remote areas.

Advisers to the European Medicines Agency have already come to their own conclusions, suggesting there’s a link between the rare clots and the vaccine, but that the potential benefits continue to outweigh any risk. That verdict led J&J to resume vaccine shipments in Europe -- a positive development for the drug giant, which has signaled optimism going into the meeting.

4. Will there be restrictions on who can get it?

It’s possible the committee will recommend limiting use of J&J’s vaccine in certain populations. The panel might say young people shouldn’t receive the shot, an approach that some European countries have taken with AstraZeneca’s vaccine. ACIP could also suggest women shouldn’t take J&J’s vaccine since the six cases seen so far have been reported in women.

Making such specific recommendations will require solid evidence. The data presented last week wasn’t enough for the committee to feel confident about setting firm guidelines.

It’s also possible ACIP will suggest new warning language that could allow providers and patients to make informed decisions. A representative from the Food and Drug Administration last week said the regulator supports this approach.

5. What happens next?

The panel could vote on recommendations during the meeting. If they approve new guidelines, the language then goes to CDC Director Rochelle Walensky for sign-off.

Use of J&J’s vaccine should resume pretty quickly if the panel OK’s it since there are millions of shots already in refrigerators across the country. But supplies of J&J’s vaccine could be limited in coming weeks as production at a key facility remains at a standstill after an FDA inspection turned up multiple problems; those don’t appear related to the side effect.

In the meantime, health officials will need to convince the public to take J&J’s shot. Americans’ confidence in Covid-19 vaccines continues to rise, according to a poll from the de Beaumont Foundation, an advocacy group focused on public health. But it has taken a toll on trust in J&J’s shot, specifically, with nearly one-third of respondents saying they’d never take the single-dose vaccine.

©2021 Bloomberg L.P.

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