People under 40 in the UK will be provided an alternative vaccine for AstraZeneca, because of concerns over rare blood clots.
Medical officials were on Friday expected to recommend that people in their 30s are offered an alternative as Britain’s recent success in fighting the coronavirus reduces risk from Covid-19.
There are no new safety concerns over the AstraZeneca-Oxford Covid-19 vaccine.
The UK medicines regulator had already recommended that those 29 and under should be offered alternative vaccines.
June Raine, the head of the Medicines and Healthcare Products Regulatory Agency, previously said the benefits of receiving the shot for older people outweighed the potential risk posed by blood clots, so the AstraZeneca drug was considered safe for them.
But she said the risk-benefit analysis was “more finely balanced” for younger people, who are less likely to succumb to serious illness from the virus.
The decision could lead to more younger people deciding to be vaccinated if fears of side effects are allayed.
People under 40 will be offered vaccines developed by Moderna and Pfizer-BioNTech, and Britain is understood to have sufficient supplies of both. There are 4.5 million people in the 30-to-39 age bracket.
The UK reported blood clots in 141 women and 100 men, aged 18 to 93, who received the AstraZeneca shot, out of about 28.5 million doses administered.
Among those cases, 49 deaths were recorded, while six cases of clotting were reported after a second dose of the vaccine.
A particular type of brain blood clot – cerebral venous sinus thrombosis – was reported in 93 cases, with an average age of 47.