SH2D3C and infection: ORF1a:K1795Q (a.k.a. NSP3:K977Q or PLPro K232Q) has been one of the commonest cryptic lineages reported from immunocompromised patients harboring persisting infections (5–10%) and in cryptic lineages from wastewaters (>50%, likely representing the most extreme persisting infections), while rare in circulating sublineages (e.g., in Gamma and BS.1), so it can be used for “carbon dating” the infection.