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Covid-19: Should we be worried about reports of myocarditis and pericarditis after mRNA vaccines?

BMJ 2021; 373 doi: (Published 24 June 2021) Cite this as: BMJ 2021;373:n1635

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Correction to: Pfizer's own data point towards an excess of mRNA vaccine harms for those aged 12-25 years

Dear Editor,

An attentive reader has kindly pointed out to me through a personal communication that in my previous rapid response [1] my computation of the number needed to treat for an additional beneficial outcome (NNTB) for preventing hospitalisation after a covid-19 infection in a healthy white male aged 25 years, i.e., ( 1 / 0.000089 ) x 3, is not 3,371, but 33,708 (due to me having likely missed a leading zero on my calculator). Therefore, the actual estimate of NNTB/NNTH (number needed to treat for an additional harmful outcome) is 223, and not 22.3. Hence, according to Pfizer’s own data [2] and the QCovid risk calculator [3], 223 young people would experience at least one serious adverse event for every prevented hospitalisation. For the best case scenario, using again the upper limit of the NNTH confidence interval, 43 individuals aged 12-25 years will experience at least one serious adverse event for each prevented hospital admission. The chance of benefits from vaccinating younger people are so vanishingly small and the risk of harms so large that the one-size-fits-all covid-19 vaccination campaign might need revision.


[1] M.T. Suadoni, Pfizer's own data point towards an excess of mRNA vaccine harms for those aged 12-25 years, (Rapid response to, BMJ Rapid Responses. (2021).

[2] R.W. Frenck, N.P. Klein, N. Kitchin, A. Gurtman, J. Absalon, S. Lockhart, J.L. Perez, E.B. Walter, S. Senders, R. Bailey, K.A. Swanson, H. Ma, X. Xu, K. Koury, W. V. Kalina, D. Cooper, T. Jennings, D.M. Brandon, S.J. Thomas, Ö. Türeci, D.B. Tresnan, S. Mather, P.R. Dormitzer, U. Şahin, K.U. Jansen, W.C. Gruber, Safety, Immunogenicity, and Efficacy of the BNT162b2 Covid-19 Vaccine in Adolescents - Supplementary Appendix, N. Engl. J. Med. (2021).

[3] University of Oxford, Welcome to the QCovid® risk calculator, (2021). (accessed June 28, 2021).

Competing interests: No competing interests

09 July 2021
Marco T Suadoni
Practice Development Nurse and Vaccination Centre Supervisor
Cambridgeshire Community Services NHS Trust
The Poynt, Poynters Road, Luton, LU4 0LA, UK