In fact, the pig that underwent anaphylaxis was immunized with Comirnaty i.v. 2 weeks before, but the absence of similar reaction in the other 2 animals in the same group, and the relatively low anti-PEG IgM (Table 1) in that animal argued against a causal role of anti-PEG IgM in the HSRs under the conditions of the present study. This evidence concerns the gene CD40LG and anaphylaxis.