CD8A and infection: These puzzling observations might suggest that CD8 T cells did not play a role in clearing infection, although it might also be possible that increased CD8 T cell frequencies in these patients reflected repeated stimulation by particularly high viral loads and/or persistent viral RNA shedding [42], thus echoing the correlation found between disease severity and high serum titres of antibodies specific for the receptor binding domain (RBD) of spike [43].