The United Kingdom’s top drug regulator on Wednesday recommended limiting the use of AstraZeneca’s coronavirus vaccine to people over the age of 30, due to a potential link to rare blood clots.
The Medicines and Healthcare products Regulatory Agency (MHRA) said blood clots were detected in an “extremely small” number of people after vaccination. The agency endorsed the overall safety of the vaccine for the “vast majority” of people, but said younger adults should be offered an alternative if one is available.
The announcement comes the same day the European Union’s top regulator found a “possible link” between the vaccine and blood clots, but did not recommend restrictions among member countries.
MHRA said it reviewed 79 reports of blood clots following the use of the University of Oxford-AstraZeneca COVID-19 vaccine, with 19 deaths. The agency said 11 out of the 19 people who died were under the age of 50, and three were under the age of 30.
During a press briefing, British officials stressed that there was no definitive link between the vaccine and blood clots, but the evidence suggested a trend for more cases in younger age groups.
Officials emphasized the vaccine is safe, and said that the benefits of it preventing hospitalization and severe cases of COVID-19 outweigh the risks. The recommendation to offer an alternative vaccine to people under 30 was being made out of abundance of caution, they said.
“We are not advising a stop to any vaccination for any individual in any age group,” said Wei Shen Lim, chairman of Britain’s Joint Committee on Vaccination and Immunization. “We are advising a preference for one vaccine over another vaccine for a particular age group, really out of the utmost caution rather than because we have any serious safety concerns.”
People in the under-30 age group who have already had a first dose of the Oxford-AstraZeneca vaccine will still be offered a second.
Jonathan Van-Tam, England’s deputy chief medical officer, said the decision is a “course correction” in the country’s vaccination program.
He acknowledged it could result in individual delays or longer distances to travel for people seeking a shot, but added that it should have a negligible effect on the speed of the country’s vaccine rollout, assuming the expected deliveries of other vaccines.
Alternatives to the AstraZeneca COVID-19 vaccine currently approved for use in the U.K. include both the Pfizer-BioNTech vaccine and Moderna’s vaccine.
AstraZeneca has not filed for authorization in the U.S.