Re: Risk of thrombocytopenia and thromboembolism after covid-19 vaccination and SARS-CoV-2 positive testing: self-controlled case series study
Dear editor,
The article by Hippisley-Cox et al. compares side effects in first-dose vaccinated people with side effects in vaccinated people suffering from a breakthrough infection with Sars-Cov-2. We know from other studies (e.g. Menni, The Lancet 21 (7), p. 939) that side effects can be much stronger after the second dose. Could unwanted effects after the second dose be as high as they are after breakthrough infection?
Meaningful comparisons would be (i) those between people who have been vaccinated once and twice and those with breakthrough infection or (ii) between those who have been vaccinated and those who are infected, but not vaccinated. The analysis even begs the question of whether the undesirable side effects could be worse after a breakthrough infection than after infection without vaccination. If one takes into account the age-related benefits and risks of vaccination, the result could even argue against vaccination of younger people.
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Re: Risk of thrombocytopenia and thromboembolism after covid-19 vaccination and SARS-CoV-2 positive testing: self-controlled case series study
Dear editor,
The article by Hippisley-Cox et al. compares side effects in first-dose vaccinated people with side effects in vaccinated people suffering from a breakthrough infection with Sars-Cov-2. We know from other studies (e.g. Menni, The Lancet 21 (7), p. 939) that side effects can be much stronger after the second dose. Could unwanted effects after the second dose be as high as they are after breakthrough infection?
Meaningful comparisons would be (i) those between people who have been vaccinated once and twice and those with breakthrough infection or (ii) between those who have been vaccinated and those who are infected, but not vaccinated. The analysis even begs the question of whether the undesirable side effects could be worse after a breakthrough infection than after infection without vaccination. If one takes into account the age-related benefits and risks of vaccination, the result could even argue against vaccination of younger people.
Competing interests: No competing interests