J&J Pause Magnifies Worry About COVID-19 Vaccine Hesitancy

Marcia Frellick

April 13, 2021

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The news today that states are being asked to pause administration of the Johnson & Johnson COVID-19 vaccine is bringing new fears of vaccine hesitancy that could push back the nation's goal for herd immunity.

The Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (FDA) are reviewing data involving six reported US cases of a rare and severe kind of blood clot — cerebral venous sinus thrombosis — in people who got the Johnson & Johnson vaccine. All six cases were in women 18 to 48 years old, and symptoms occurred 6 to 13 days after their vaccination.

More than 6.8 million doses of the Johnson & Johnson vaccine have been administered in the United States.

William Schaffner, MD, an infectious disease expert at Vanderbilt University School of Medicine in Nashville, Tennessee, told Medscape Medical News that several messages are important to emphasize given the potential for more hesitancy.

"One is that our safety surveillance system is very comprehensive," he said. "It is very sensitive and it works, and we're being transparent about it."

Another is that the number of cases being reviewed is literally one in a million.

"We're talking about needles in haystacks here," Schaffner said. "These blood-clotting events are an even smaller risk than the blood-clotting events associated with birth control pills."

He said he has heard questions about why the potential complications weren't caught earlier and criticism that the complications are proof the trial was rushed.

"That's not the case," Schaffner explained. "When you have a trial of only 15,000 people — though that's a huge trial — if you have a risk that is 1 in a million, it's very unlikely to show up in the trial. You have to monitor what happens when you start using drugs or vaccines in the real world and you give it to literally millions of people."

The CDC will convene its Advisory Committee on Immunization Practices on Wednesday to review the cases, and the FDA will also review them.

Schaffner said he hopes and expects after a review that Johnson & Johnson vaccine administration can resume, perhaps with restrictions, as some European countries have placed on the AstraZeneca vaccine.

The Johnson & Johnson vaccine is one of three vaccines approved for emergency use in the United States. The vaccines from Moderna and Pfizer-BioNTech use messenger RNA instead of adenovirus and no serious side effects have been reported in the tens of millions in the United States who have received those shots.

Johnson & Johnson said in a statement, "The health authorities advise that people who have received our COVID-19 vaccine and develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their healthcare provider."

Tim Schacker, MD, vice dean for research and an infectious disease physician at the University of Minnesota Medical School in Minneapolis, told Medscape Medical News that the Johnson & Johnson news today is another barrier to achieving herd immunity, a goal for which "we already had a long way to go."

A national survey finds that to be the case as well.

Last week, Surgo Ventures released the results of its second survey on enthusiasm for receiving a COVID-19 vaccine and found that acceptance is generally high, with 59% of the population now saying they have already been vaccinated or want to be as soon as they can get one.

That was up from 40% in Surgo's first survey, conducted in early January.

However, the survey authors said in a press release that respondents' answers to when they would get a shot — "as soon as it's available," "in three months," "in a year," etc. — combined with current vaccination rates suggest that doses could start to outpace demand by the end of this month, which is earlier than expected. And that's long before the nation reaches the 70%-90% threshold needed for herd immunity.

Benefit Outweighs Risk

Schacker applauded the decision to halt administration of the Johnson & Johnson vaccine.

"I think the FDA and the CDC did exactly the right thing by pausing for a day or two to look at the data and make an assessment," he said.

He said it's also important to remember that all medications come with risks.

"With people on Lipitor (atorvastatin), the risk of muscle necrosis, known as rhabdomyolysis — which people can die from — is 1 in 100,000, 10 times greater than the blood clot risk talked about with J&J. I don't mean to trivialize it," Schacker said. "I'm just saying we're all on medications that have risks."

He said he also hopes the reviews in the next couple of days will clear the Johnson & Johnson vaccine for use because it has advantages over the others: it doesn't have the same requirements for refrigeration, it's one dose, and it's a key to vaccinating those in hard-to-reach populations.

"The benefits of any of the COVID vaccines, I think, outweigh the risks," he said.

Schaffner and Schacker declared no relevant financial relationships.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News, and Nurse.com, and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick.

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