Vaccine advisers in the UK said they were not recommending the universal vaccination of 12- to 15-year-olds against COVID-19, preferring to take a precautionary approach to assess the long-term impacts of rare heart inflammation.

There have been reports of heart inflammation, known as myocarditis, in young people following vaccination with Pfizer's shot, though the condition is usually mild.

Britain's Joint Committee on Vaccination and Immunization said on Friday it was expanding the eligibility for COVID-19 vaccinations to more 12- to 15-year-olds with underlying health conditions than previously but said the benefits of vaccination for healthy children were likely small.