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After almost two weeks on pause, Johnson and Johnson’s one-shot COVID-19 vaccine was recommended as safe to resume by a panel of experts at the Centers for Disease Control. The group concluded that the benefits of the vaccine outweigh the risks. Federal health officials should allow for vaccination sites across the country to resume use shortly. The shot is the third vaccine that protects against COVID-19 to gain emergency use authorization from the FDA.
Last week, the FDA and the CDC released a joint statement, effectively placing the J&J vaccine on pause after six women developed severe blood clots shortly after getting vaccinated. While the blood clots were incredibly rare, health officials said the pause was done “out of an abundance of caution.”
The panel of experts, known as the Advisory Committee on Immunization Practices, met for a daylong session where they discussed the recent clots and their potential connection to the vaccine. The committee also presented data with nine new cases of blood clots linked to Johnson and Johnson’s vaccine. In total, there have been 15 reported cases of this rare condition, all of whom have been women.
The type of blood clots these 15 women experienced is what’s known as cerebral venous sinus thrombosis, or CVST. It occurs when a blood clot forms in the venous sinuses in the brain, and if untreated, it can hemorrhage. In addition to CVST, the women also experienced significantly low platelets, which prevents blood from clotting. All of these symptoms occurred within two weeks of receiving the shot. Similar blood clots have also been reported in Europe in conjunction with the AstraZeneca COVID-19 vaccine.
While the condition is rare, the treatment for it is unlike that of traditional therapies to combat blood clots, which often include putting the person on a blood thinner such as heparin. And part of the pause on the J&J vaccine was to give public health researchers and physicians time to understand the condition better—including how to spot it and how to treat it. Giving a patient with low platelet counts a blood thinner is risky and can be fatal, so special treatment guidance is required so that emergency room physicians don’t give heparin to someone with this rare condition.
[Read more: The pause on Johnson & Johnson’s COVID vaccine doesn’t mean it’s not safe]
Following investigations over these past two weeks, the CDC panel concluded that the benefits outweigh the risk of developing this clotting disorder. The chances of developing CVST after receiving the J&J shot is exceedingly low. However, when it does occur it incredibly dangerous. In the day-long meeting, Tom Shimabukuro, the deputy director of the CDC’s Immunization Safety Office, called the condition “rare but clinically serious,” according to The New York Times. Shimabukuro also said in the meeting that there had been no reports of the condition in the cohort of people who received the Pfizer COVID-19 vaccine. In those who received Moderna’s COVID-19 vaccine, there were three reports of people developing CVST, though they did not have the signature low platelet levels that make the condition even more dangerous.
After taking all of this into consideration, the CDC panel concluded that the benefits of restarting the J&J vaccine outweigh the risks of withholding it. Furthermore, experts in the meeting said that if the J&J were to not resume, it would delay the goal of getting all Americans their shots by 14 days.
“We could expect that if 1 million people in the United States were vaccinated with the J&J single-dose vaccine, there would be over 2,000 fewer deaths and 6,000 fewer COVID-related hospitalizations,” Joanne Waldstreicher, J&J’s chief medical officer told CNBC. In contrast, it would cause just 26 to 45 clot cases.
The committee concluded that the J&J COVID-19 should continue with a warning label that explains the blood clot risk.