CDC Has Confirmed 54 Cases of Clotting in Adults Who Took J&J COVID Vaccine

A Centers for Disease Control and Prevention advisory panel recommended that Americans get the Moderna or Pfizer COVID-19 vaccine over a Johnson & Johnson jab, which carries a risk of a rare blood clot that has killed nine people, the Associated Press reported.

Dr. Isaac See of the CDC said 54 clot cases have been confirmed in adults, and that there are another two deaths suspected to be due to the J&J vaccine in addition to the nine confirmed fatalities.

This recommendation, which CDC Director Rochelle Walensky still has to choose to accept, would change the previously held public opinion that the three vaccine choices are all equal.

Out of 200 million fully vaccinated Americans, about 16 million received the J&J shot. According to the Food and Drug Administration, about one in 100,000 vaccine doses have gotten the clot. But the CDC panel sees the clot as dangerous enough to recommend the other vaccines – which pose no clot risk – above it.

Earlier in the pandemic, the J&J vaccine was seen as an easier choice, as it only required one dose when the others required two. It was especially useful for groups such as homeless people, who authorities could not guarantee would go to get two doses.

But now that vaccines are more readily available in the U.S., the CDC is more heavily considering the J&J shot's potential risks.

COVID-19, vaccine, Johnson & Johnson
A government advisory panel met Thursday, Dec. 16, to determine if any restrictions are needed to the Johnson & Johnson COVID-19 vaccine because of rare but serious blood clots. Above, a member of the Philadelphia Fire Department prepares a dose of the Johnson & Johnson COVID-19 vaccine at a vaccination site setup in Philadelphia, on March 26. Matt Rourke, File/AP Photo

A strange clotting problem prompted the U.S. to temporarily halt the single-dose J&J shots last April while scientists investigated. Eventually, regulators decided the benefits of a one-and-done vaccine outweighed what was considered a very rare risk—as long as recipients were warned.

While it's still rare, the FDA told health care providers this week that more cases have occurred since the spring.

The CDC decides how vaccines should be used in the U.S., and its influential advisory committee is deliberating whether the newest safety data warrants any new limits on J&J's vaccine.

The other two vaccines used in the U.S.—from Pfizer and Moderna—are made differently and regulators say they don't come with this clot risk. And unlike in the spring when vaccine supplies were tight, Pfizer and Moderna shots now are plentiful in the U.S.

COVID-19 itself can cause potentially deadly blood clots. But the suspect culprit for the vaccine-related kind is a rogue immune response linked to both the J&J shot and a COVID-19 vaccine made by AstraZeneca. Both of those vaccines are made similarly, using a cold virus known as an adenovirus, although AstraZeneca's shot is not used in the U.S.

The FDA this week warned that another dose of the J&J vaccine shouldn't be given to anyone who developed a clot following either a J&J or AstraZeneca shot.

At issue is a weird kind of blood clot that forms in unusual places, such as veins that drain blood from the brain, and in patients who also develop abnormally low levels of the platelets that form clots. Symptoms of the unusual clots, dubbed "thrombosis with thrombocytopenia syndrome," include severe headaches a week or two after the J&J vaccination—not right away—as well as abdominal pain and nausea.

Several other countries already have recommended age restrictions for both the AstraZeneca and J&J vaccines, or that preference be given to the Pfizer and Moderna vaccines.

The Associated Press contributed to this report.

California, vaccine, Johnson & Johnson
A CDC advisory panel recommended Americans choose the Moderna or Pfizer vaccine over a Johnson & Johnson jab to a rare blood clot risk. Above, licensed vocational nurse LeShay Brown administers the new one-shot Johnson & Johnson COVID-19 vaccine to California Health and Human Services Secretary Dr. Mark Ghaly at a vaccination event at Baldwin Hills Crenshaw Plaza on March 11 in Los Angeles, California. Photo by Mario Tama/Getty Images