British authorities recommend not giving the AstraZeneca vaccine to those under 30 if possible amid clot fears.

Regulators emphasized that benefits of receiving the vaccine continue to outweigh the risks for most people

— British authorities recommended Wednesday that the AstraZeneca COVID-19 vaccine not be given to adults under 30 where possible because of strengthening evidence that the shot may be linked to rare blood clots.

The recommendation came as regulators in the United Kingdom and the European Union emphasized that the benefits of receiving the vaccine continue to outweigh the risks for most people — even though the European

Medicines Agency said it had found a “possible link” between the shot and the rare clots. British authorities recommended that people under 30 be offered alternatives to AstraZeneca. But the EMA advised no such age restrictions, leaving it up to its member-countries to decide whether to limit its use.

Several countries have already imposed limits on who can receive the vaccine, and any restrictions are closely watched since the vaccine, which is cheaper and easier to store than many others, is critical to global immunization campaigns and is a pillar of the U.N.-backed program known as COVAX that aims to get vaccines to some of the world’s poorest countries.

“This is a course correction, there’s no question about that,” Jonathan VanTam, England’s deputy chief medical officer, said during a news briefing.

Van-Tam said the effect on Britain’s vaccination timetable — one of the speediest in the world — should be “zero or negligible,” assuming the National Health Service receives expected deliveries of other vaccines, including those produced by Pfizer-BioNTech and Moderna.

EU and U.K. regulators held simultaneous news conferences Wednesday to announce the results of investigations into reports of blood clots that sparked concern about the rollout of the AstraZeneca vaccine.

The EU agency described the clots as “very rare” side effects.

Dr. Sabine Straus, chair of its Safety Committee, said the best data was from Germany, where there was one report of the clots for every 100,000 doses given, although she noted far fewer reports in the U.K. Still, that’s less than the clot risk that healthy women face from birth control pills, noted another expert, Dr. Peter Arlett.