After reports of rare heart inflammation cases among adolescents following the Pfizer vaccine shot, some countries have tweaked their vaccination programmes for teens.  The countries have either halted administering mRNA-based vaccines to teens or giving only one dose of the Covid shots to prevent the possible rare cardiovascular side effects.

UK’s Joint Committee on Vaccination and Immunisation (JCVI) recently stopped short of advising against administering the Pfizer vaccine in healthy adolescents. The committee had said that the margin of benefit against risk is “too small” to advise on a universal programme of vaccination for healthy 12 to 15-year-old children.

While the United States has continued to administer the Pfizer vaccine to adolescents, it had issued a warning to watch for the symptoms of myocarditis, the rare inflammatory heart condition.

In July, European Medicines Agency said that it had found a possible link between myocarditis and mRNA-based Covid-19 vaccines. Pfizer-BioNTech and Moderna have developed mRNA-based vaccines which are being used in the United States on a massive scale to vaccinate the population.

Here are some of the steps some countries are taking:

United Kingdom

Britain has opted for a cautionary approach in administering mRNA-based vaccines by offering only the first shot Pfizer-BioNTech Covid-19 vaccine. The second dose of the two-dose regimen will not be offered until at least spring when there may be more data on the cases.

Sweden

Citing an unpublished Nordic study, Sweden has decided to halt the use of Moderna’s Covid-19 vaccine for younger groups. The Swedish health agency said it would pause using Moderna’s Covid shot for people born in 1991 and later.

Norway

The Scandinavian country has been offering only one dose of Pfizer-BioNTech vaccine to children aged 12-15.

Denmark

The Danish Health Agency has clarified that the statement suggesting suspension of Moderna’s vaccine use was in fact a miscommunication. Denmark on Friday said that it was continuing the use of mRNA-based vaccine among under-18s.

Finland

Data from some studies have suggested that reported cases of rare heart inflammation were higher after receiving Moderna’s Covid-19 vaccine compared with the Pfizer-BioNTech shots. Finland has halted the use of the Moderna vaccine to men born in 1991 and later and instead offer Pfizer’s vaccine.

Hong Kong

An advisory panel to the Hong Kong government has recommended that children aged 12-17 should get only one dose of Pfizer-BioNTech’s Covid-19 vaccine.