select search filters
roundups & rapid reactions
before the headlines
Fiona fox's blog

expert reaction to US case series study in children study looking at association of myocarditis with the Pfizer-BioNTech COVID-19 vaccine

A study published in JAMA Cardiology looks at the association of myocarditis with Pfizer-BioNTech COVID-19 vaccine in a case series of children in the US.


Prof Peter Openshaw, Professor of Experimental Medicine, Imperial College London, said:

“In this case series, 15 cases of myocarditis are described from a single paediatric referral centre in May, June and July 2021.  Each had been given the Pfizer mRNA vaccine between 1 and 6 days prior to diagnosis; children were aged 12-18 years.  In addition to chest pain, most had fever and muscle pain with evidence of inflammation of the heart muscle evident on tests.  All cases were relatively mild and most resolved completely without treatment.  All but one case was male, and most were after the 2nd dose.

“The problem with case series of this type is the lack of comparison groups.  How many cases of myocarditis might be seen in normal children, or those given other vaccines (including those that are not for COVID), or in teenagers infected with SARS-CoV-2?

“As the authors note, myocarditis does happen after other vaccines.  The estimated rate (62.8 cases per million) makes this a rare event.  To put this in context, the authors point out that COVID-19 vaccination in males aged 12 to 29 years would prevent 11,000 COVID-19 cases, 560 hospitalizations, 138 intensive care unit admissions and 6 deaths compared with 39 to 47 expected case of myocarditis, if the link with the vaccine is causal.

“In another recent study that has not yet been peer-reviewed (, the authors estimated that males aged 12 to 17 were most likely to develop myocarditis within three months of catching covid-19, at a rate of about 450 cases per million infections.  Mendel Singer at Case Western Reserve University in Ohio (an author on this study) said: “If you’re focused on heart inflammation, the safer bet is to take the vaccine.”  The calculations on which this statement is based are still under discussion, but my view that teenagers should be considered for vaccination is not changed by this new publication.”



‘Association of Myocarditis With BNT162b2 Messenger RNA COVID-19 Vaccine in a Case Series of Children’ by Audrey Dionne et al. was published in JAMA Cardiology at 16:00 UK time on Tuesday 10 August 2021.

DOI: 10.1001/jamacardio.2021.3471



All our previous output on this subject can be seen at this weblink:



Declared interests

Prof Peter Openshaw: “Peter Openshaw has served on scientific advisory boards for Janssen/J&J, Oxford Immunotech, GSK, Nestle and Pfizer in relation to immunity to viruses (fees paid to Imperial College London).”

in this section

filter RoundUps by year

search by tag