The U.S. is recommending a “pause” in administration of the single-dose Johnson & Johnson COVID-19 vaccine to investigate reports of potentially dangerous blood clots.
In a joint statement Tuesday, the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) said they were investigating the reports of reduced platelet counts and blood clots that occurred in six women in the two weeks following vaccination.
Among the six cases, one woman died and another is in critical condition.
CDC’s Advisory Committee on Immunization Practices says they will be meeting on Wednesday to further discuss the blood clot cases.
“Until that process is complete, we are recommending a pause in the use of this vaccine out of an abundance of caution,” Dr. Anne Schuchat, Principal Deputy Director of the CDC and Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research said in a joint statement.
Federal distributors of the shot will cease administering it and other providers, including states, are expected to follow suit.
More than 6.8 million doses of the Johnson & Johnson vaccine have been administered in the U.S to date.
Dr. Paul Offit is a member of the FDA vaccine advisory committee and says the clots didn’t come up in trials because it is such a rare event.
“If you look at the way that J&J did their trial, it was roughly a 44,000 person trial, if an event is occurring in one and a million people you are unlikely to see that,” says Offit. “It should be reassuring to people that we are always looking to make sure that there isn’t even a very, very rare side effect.”
In Canada, the single-dose vaccine has been approved for use by Health Canada though it has yet to be delivered and distributed. Doses were expected to start arriving in May, there has been no word on who would be prioritized for the single-dose vaccine.
Canada has pre-ordered 10 million doses of the shot with an option to order 20 million more.
The rollout of the Oxford-AstraZaneca vaccine in this country has been shrouded with confusion over blood clot concerns and changing guidance over who can receive the shot.
Canada’s National Advisory Committee on Immunization (NACI) recently recommended a pause on AstraZeneca vaccinations for people under 55 due to safety reasons.
The advisory committee’s concerns stemmed from a possible link between the shot and rare blood clots.
The NACI says cases identified have been primarily in women under the age of 55 years but note that cases in men have also been reported and have mostly occurred between 4 and 16 days after administration.
They said that adults 55 years of age and older may still be offered the AstraZeneca vaccine with informed consent.
The drugmaker updated the efficacy data for its vaccine last month and say the shot is 76 per cent effective against mild symptoms and 100 per cent effective at preventing severe disease from the virus. In trial volunteers aged 65 and older, the vaccine was 85 per cent effective in preventing symptoms.
Canadian health officials first recommended the AstraZeneca vaccine for those under 65, but on March 16 it adjusted its advice to say that it could also be given to seniors.
With files from the Associated Press