Max Schmeling, Vibeke Manniche & Peter Riis Hansen

… Vaccine vials with individual doses are supplied in batches with stringent quality control to ensure batch and dose uniformity.2 Clinical data on individual vaccine batch levels have not been reported and batch- dependent variation in the clinical efficacy and safety of authorized vaccines would appear to be highly unlikely. However, not least in view of the emergency use market authorization and rapid implementation of large-scale vaccination programs, the possibility of batch-dependent variation appears worthy of investigation. We therefore examined rates of SAEs between different BNT162b2 vac- cine batches administered in Denmark (population 5.8 million) from 27 December 2020 to 11 January 2022.

… The observed variation in SAE rates and seriousness between BTN162b2 vaccine batches in this nationwide study was contrary to the expected homogenous rate and distribution of SAEs between batches … identification of such effects evidently requires that observed adverse events are linked with the respective individual batch labels and sizes (dose numbers).

… In conclusion, the results suggest the existence of a batch-dependent safety signal for the BNT162b2 vaccine, and more studies are war- ranted to explore this preliminary observation and its consequences.

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