Waning humoral immunity after mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a significant problem for public health. Breakthrough infection in hospitals over several months after vaccination has not been fully characterized. especially against the delta (B. 1. https://ilywarpw34b7u.theisblog.com/35130693/the-relationship-between-humans-and-other-animals-in-european-animal-welfare-legislation