PROS1 and COVID-19: According to our knowledge, downregulation of protocadherins and type I interferons by the S protein at an early (5 hours) time-point post-transfection is a novel finding, and should be taken into consideration in the context of vaccination strategies, as this may result in the activation of other latent viral infections; such as EBV infection in vaccinated individuals or during the course of COVID-19 (68, 69).