After the Centers for Disease Control and Prevention and the Food and Drug Administration announced that they were investigating unusual clots in six women between the ages of 18 and 48 and the death of one person died following inoculation with the single-dose Johnson & Johnson COVID-19 vaccine, the US government recommended a “pause” in using the vaccine. The government plans to investigate reports of rare but potentially dangerous blood clots, setting off a global chain reaction worldwide and setting back the worldwide vaccination campaign.
While the acting FDA commissioner expected the pause to last only a few days, the decision caused swift action in Europe and elsewhere as the drug company and regulators moved to stop the use of the J&J vaccine, at least temporarily. Hundreds of thousands of doses were supposed to arrive in European countries this week. European countries have had supply shortages, logistical problems and concerns over blood clots in a small number of people who received the AstraZeneca vaccine.
The Associated Press reported that any slowdown in the dissemination of the shots could have broad implications for the global vaccination effort. The J&J vaccine’s single-dose regimen and relatively simple storage requirements would make it easier to use, especially in less affluent countries. The clots, which occurred 6 to 13 days after vaccination in veins that drain blood from the brain, occurred together with low platelets, the fragments in blood that normally form clots. More than 6.8 million doses of the J&J vaccine have been administered in the US, the vast majority with no or mild side effects. There were only six confirmed cases of blood clots.
According to the FDA, cases under investigation seem to be similar to the clots that European authorities say are possibly linked to the AstraZeneca vaccine, which is not yet cleared in the U.S. European regulators have emphasized that the AstraZeneca risk appears to be lower than the possibility of developing clots from birth control pills.
Federally run mass vaccination sites and some states will pause the use of the J&J shot. Authorities have not found clot problems with the Moderna and Pfizer vaccines.
Acting FDA Commissioner Janet Woodcock said, “I’d like to stress these events appear to be extremely rare. However, COVID-19 vaccine safety is a top priority.”
Dr. Anthony Fauci, the nation’s top expert on infectious disease, said the pause would enable the FDA and the CDC to investigate the clotting cases “to try and understand some of the mechanisms” and “to make physicians more aware of this.” A CDC committee will meet Wednesday to discuss the cases, and the FDA has also launched an investigation into the cause of the clots and low platelet counts.
Tuesday’s action was not a mandate, FDA officials explained. Doctors and patients are still allowed to use J&J’s vaccine if they decide its benefits outweigh its risks for individual cases, according to Dr. Peter Marks. The FDA and the CDC recommend that people who were given the J&J vaccine should contact their doctor if they experience severe headache, abdominal pain, leg pain or shortness of breath within three weeks.
J&J said that it was aware of the reports of blood clots, but that no link to its vaccine had been established. The company also said it would delay the rollout of its vaccine in Europe as a precaution.
US health authorities cautioned doctors against using a typical clot treatment, the blood-thinner heparin. European authorities investigating the AstraZeneca cases have said that the clots appear to be similar to a very rare abnormal immune response that sometimes strikes people treated with heparin, leading to a temporary clotting disorder.
Even without J&J’s vaccine, White House officials said they will have enough supplies to vaccinate most American adults by the summer. According to Jeff Zients, the White House’s COVID-19 response coordinator, “We believe there’s enough vaccine in the system — Moderna and Pfizer — for all Americans who want to get vaccinated by May 31 to do so.”