The CDC and FDA have recommended the U.S. pause use of Johnson & Johnson's COVID-19 vaccine while they review six reports of rare and serious blood clots in people who've received the shot.
The FDA said April 13 that six cases of blood clots called cerebral venous sinus thrombosis were seen in combination with low levels of blood platelets. All occurred in women between the ages of 18 and 48 and their symptoms began six to 13 days after vaccination.
One of the women died and a second has been hospitalized in critical condition, according to The New York Times.
There are too few cases to determine who may be more susceptible to the blood clots, Janet Woodcock, MD, acting FDA commissioner, said during an April 13 media briefing held by the FDA and CDC.
The treatment of this specific type of blood clot is different from a typical blood clot. Usually, an anticoagulant drug, heparin, would be used to treat a blood clot, but with a cerebral venous sinus thrombosis blood clot, giving heparin may be dangerous, the FDA said. The agency said it's recommending pausing the use of the vaccine so healthcare providers can plan for the proper recognition and treatment of this type of blood clot.
Dr. Woodcock said she only expects the pause to last a few days.
The CDC is holding an emergency meeting April 14 to further review the cases and is recommending the pause until the review is complete out of an "abundance of caution."
Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research, said that the agency’s recommendation is not a mandate. He said that if a healthcare provider has a discussion with a patient in which they agree the benefits of receiving Johnson & Johnson’s vaccine outweigh the risks, they will be allowed to administer the shot.
Dr. Marks said the pause will probably not have an effect on the country’s ability to reach President Joe Biden’s goal of administering 200 million COVID-19 vaccine doses by his 100th day in office.
The White House said April 13 that the pause won't have a "significant impact" on the national vaccine effort because there's still a steady supply of Pfizer and Moderna vaccines, The Hill reported.
"This is more than enough supply to continue the current pace of vaccinations of 3 million shots per day, and meet the president’s goal of 200 million shots by his 100th day in office — and continue on to reach every adult who wants to be vaccinated," said Jeff Zients, the White House's COVID-19 response coordinator. He added that the Johnson & Johnson vaccine makes up less than 5 percent of the vaccines given in the U.S. so far.
Mr. Zients said the White House is working with states to get everyone scheduled for Johnson & Johnson vaccines quickly rescheduled for a Pfizer or Moderna vaccine, The Hill reported.
As of April 12, more than 6.8 million doses of Johnson & Johnson's vaccine have been administered in the U.S.
The FDA said people who've received Johnson & Johnson's vaccine who develop severe headache, abdominal pain, leg pain or shortness of breath within three weeks after vaccination should contact their healthcare provider.
Johnson & Johnson said in a statement that it is "aware of an extremely rare disorder involving people with blood clots in combination with low platelets in a small number of individuals who have received our COVID-19 vaccine."
It added that it has made the decision to "proactively delay the rollout of our vaccine in Europe."
The same type of rare blood clotting events have been seen after vaccination with AstraZeneca's COVID-19 shot. Both vaccines are viral vector vaccines, which means they use a modified version of a virus to deliver instructions to cells, according to the CDC. But there is no obvious reason this type of vaccine would cause the type of rare blood clots that have been seen, the Times reported.
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