Thread by @petermbenglish

1/ It's hard to know the real reason for the decision to give 12-15-year-olds only a single dose of because the details of the discussion are not available. Hence the campaign for greater JCVI transparency.

@DrRCoull @cv_cev twitter.com/DrRCoull/statu…

2/ The purported reason for the decision, IIRC, is a concern about adverse reactions to the vaccine.

Myocarditis, in particular, seems to occur in an extremely small proportion of vaccine recipients.

3/ Post-vaccination cases seem to have a minor illness and make a full recovery, although some people are concerned there could be long term consequences.

Myocarditis is far more common after Covid-19 disease than after vaccination.

4/ Post-vaccination myocarditis seems most common after the second dose of vaccine. This is the reason put forward for - at present - offering 12-15-yos a single dose.

5/ Ideas about the high proportion who had been infected already - which usually seems to have a similar effect as a first dose of vaccine - and about the perceived lack of severity of disease in this age group are likely also considerations.

6/ Long Covid seems not to have been a consideration.

I think the decision was said to be an interim decision, to be kept under review; in particular, while further data on vaccine safety in this age group accumulated from countries giving two doses.

7/ My expectation was that it would change after a few weeks or months, after which a second dose would be offered.

8/ Indeed, I think it's likely, in due course, that we'll move to it being a three-dose primary course for everyone, perhaps with boosters every few years, possibly starting in infancy.

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