From the BBC. www.bbc.co.uk/news/health-58423152
Research on millions of people who've had the mRNA vaccines (Pfizer and Moderna) shows there's a tiny risk of myocarditis, or inflammation of the heart, which is more common in young people - and particularly younger boys - after a second dose. It can cause chest pain and a pounding heart, but symptoms usually clear up in days.
No vaccine or drug is ever 100% safe, and data from the US shows the numbers of children affected are very small.
For every million Pfizer second doses given to 12-17-year-old-boys, around 60 had the condition (compared with 8 in a million among girls). The rates in this age group are higher than in older ones - and it's why only one dose for 16 and 17-year-olds in the UK has been recommended, for now.
But being infected with Covid has consequences for teenagers' health too - including their hearts - so how big is that risk?
"A key unknown is the risk of myocarditis from Covid infection itself," says Prof Neil Ferguson, a government adviser, from Imperial College London.
"If it's similar or higher than from vaccination, then vaccination is more likely to be beneficial." But he says it's "not possible" to give a definitive answer now.
There is also very little data on the long-term effects of heart inflammation years down the line.
Until there is more data, given DS is male and also an athlete, doing c.20hrs of sport a week, I'm really reluctant. I may reconsider once the roll out starts, but I am worried about it.