CDC Panel Leaves J&J Pause in Place for at Least a Week

Marcia Frellick

April 14, 2021

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The Center for Disease Control and Prevention's (CDC's) Advisory Committee on Immunization Practices (ACIP) decided Wednesday at the end of an emergency meeting that it did not have adequate information to change the current paused status of the Johnson & Johnson COVID-19 vaccine.  

On Tuesday, the CDC and the US Food and Drug Administration (FDA) recommended that Johnson & Johnson vaccinations be paused after reports of blood clots in six patients among the more than 7 million people who had received the Johnson & Johnson vaccine in the United States.

A member of the committee, Beth Bell, MD, MPH, emphasized, "I do not want to be sending a message that there is some huge concern here on a different order of magnitude than any other vaccine safety signals that we evaluate. And I don't want to send a message that there is something fundamentally wrong with the vaccine because that also I don't agree with."

At the end of the 4-hour meeting, voting and nonvoting ACIP members who spoke generally supported those sentiments and decided to set a meeting for 1-2 weeks from now and evaluate more safety data at that time.

Some, however, pointed out that delaying a decision could have substantial consequences in terms of unused vaccine doses and public confidence.

Committee member Camille Kotton, MD, described the pause as "devastating."

"Putting this vaccine on pause for those of us that are frontline healthcare workers has really been devastating," she said. "I agree in general that we don't have enough data to make a decision at this time but we were planning on using this vaccine in the state of Massachusetts for people who were homebound and otherwise not able to get a vaccine. We were planning on using it for our vulnerable inpatient population often with many comorbidities and at high risk for disease but haven't been able to get vaccinated otherwise."

Pausing the one-and-done vaccine that doesn't have the significant refrigeration requirements of the others "is a significant loss," added Kotton, who is with the Infectious Diseases Division at Massachusetts General Hospital in Boston.

What Is Known, Not Known

Sara Oliver, MD, who leads the CDC's COVID-19 Vaccines ACIP Work Group, summarized what is known and unknown at this point.

Among the six cases of rare but serious cerebral venous sinus thrombosis (CVST) reported to the Vaccine Adverse Event Reporting System after the Johnson & Johnson shot, all were women 18-48 years of age with a period of vaccine to symptom onset of 6-13 days.

No cases of CVST with thrombocytopenia have been reported after receipt of Pfizer or Moderna shots, she noted.

In the United States, the two mRNA vaccine alternatives are available, "and based on current projections supply of both vaccines are expected to be relatively stable in the near future," Oliver said.

She said 14 million doses of Pfizer and Moderna are expected each week in the United States, and Johnson & Johnson vaccines make up less than 5% of vaccines administered in the United States.

Approximately 13 million Johnson & Johnson doses are available to order or are already at administration sites in the United States, Oliver added.

But much more is unknown. "Currently we don't know the true background incidence of CVST with thrombocytopenia. We don't know the specific risk factors for these events. We don't know the incidence of other thrombotic cases with thrombocytopenia, so non-CVST after the [J&J] vaccine. We don't know the ability to compare or generalize the thrombotic cases seen after the AstraZeneca vaccine to the [J&J] vaccine cases.

"Finally, we don't know the true incidence of thrombotic events after the [J&J] vaccine as there may be more cases identified in the coming days to weeks," Oliver said, referring back to the average time from vaccination to symptom onset.

Scott Ratzan, MD, editor-in-chief of the Journal of Health Communication: International Perspectives, applauded ACIP's delay on making a decision.

Ratzan, who watched the deliberations online, told Medscape Medical News that the decision "shows an admirable abundance of caution in the distribution of COVID-19 vaccines."

"Unfortunately," he said, "the pause also worsens the existing and pervasive vaccine hesitancy issue."

"We need a rational strategy regarding who should or should not get the J&J/Janssen vaccine since these rare adverse events appear to affect a particular group of people, females aged 18-48. It is essential that we build vaccine confidence and retain the option of using this vaccine for people who are not in this risk group," said Ratzan, who is also executive director of Business Partners to CONVINCE (BP2C), a global network of employers that promotes COVID-19 vaccination among employees, suppliers, and customers.

He pointed out that there are no safety red flags with the Pfizer and Moderna COVID-19 vaccines.

"We should feel reassured about the process of ensuring vaccine safety as the FDA and CDC have quickly addressed risk and shared the data transparently of the J&J vaccine and taken appropriate action," he said.

ACIP's executive secretary, Amanda Cohn, MD, said the date for the next meeting would be set by Friday.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News, and, 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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