Acute Appendicitis After COVID-19 Vaccines in Italy: A Self-Controlled Case Series Study.

There was no evidence of association of BNT162b, ChAdOx1-S, mRNA-1273 and Ad26.COV2-S with acute appendicitis in the general population. The results of the subgroup analyses by sex needs to be considered with caution. The multiplicity issue cannot be excluded being these hypotheses two of several hypotheses tested. In addition, relevant literature on the biological mechanism of the disease and evidence of similar effects with other vaccines or with the same vaccines are still lacking to provide strong support for a conclusion that there is an harmful effect in males and females with mRNA-1273 and Ad26.COV2-S.