An expert advisory committee to the Centers for Disease Control and Prevention decided Wednesday it needed more time to consider whether to recommend to resume administering the COVID-19 vaccine made by Johnson & Johnson.
The committee's emergency meeting took place less than 36 hours after the CDC and the Food and Drug Administration called for a voluntary pause after receiving reports of serious side effects seen in six women who had received the Johnson & Johnson vaccine.
The advisory committee will reconsider a recommendation within the next 10 days. It declined to vote on a question of whether vaccinations might continue, perhaps with limits on who would receive it, effectively leaving the current pause in vaccinations in place.
The committee heard details about the cases, which all occurred in women aged 18 to 48. Each developed a severe blood clotting disorder called cerebral venous sinus thrombosis (CVST) within 6 to 13 days after receiving the vaccine. There were no factors identified in the women that would have raised their risk of these serious blood clots.
About 7.2 million doses of the one-dose vaccine have been administered in the U.S. so far. The CDC expects a few more cases may be reported from those who have been vaccinated in the past two weeks.
The CVST disorder occurs when a blood clot forms that prevents blood from draining out of the brain. As a result, blood cells may break and leak blood into the brain tissues, forming a hemorrhage. One common early sign of the syndrome is severe headache, much like one would experience with a stroke.
A 45-year-old woman died of CVST in mid-March after receiving the vaccine. Three women remain hospitalized; two have recovered and are at home, according to Dr. Tom Shimabukuro of the CDC's COVID-19 Vaccine Task Force.
White House officials sought to reassure the public on vaccine safety.
"We don't expect any significant impact whatsoever" on the availability of vaccines, White House COVID-19 response coordinator Jeff Zients told reporters earlier in the day.
He emphasized that vaccine makers Pfizer and Moderna were on track to deliver tens of millions of doses in coming weeks. This week, 28 million doses of both vaccines allocated. Supplies of Johnson & Johnson were already expected to be below 1 million a week before the pause, due to a disruption at a manufacturing facility in Baltimore.
CDC director Rochelle Walensky said that officials are working to reschedule vaccine appointments for people were going to receive the Johnson & Johnson vaccine during the pause.