CD4 and infection: Higher CD95 expression in CD4 + and CD8 + cells are found to be associated with decreased CD4 + and CD8 + cell numbers respectively, showing apoptosis via CD95 is a potential mechanism for COVID-19-induced lymphopenia.91 There is an increased rate of infection associated with the ORF3a mutation in SARS-CoV-2 and there are 18 distinct amino acid substitutions observed; five are neutral (T175I, L94F, K16N, L94I, and A72 T), whereas the rest are detrimental (Q57H, G251 V, P25L, V90F, W149L, R126 T, T176I Y109C, D155Y, T217I, D142N Y156N andK67E).