Absence of SARS-CoV-2 antibodies in pre-pandemic plasma from children and adults in Vietnam.
Chau NVV., Nhan LNT., Nguyet LA., Tu NTK., Hong NTT., Man DNH., Ty DTB., Nhu LNT., Yen LM., Khanh TH., Quy DT., Minh NNQ., Ny NTH., Anderson D., Wang L-F., van Doorn HR., Hung NT., Thanh TT., Thwaites G., Van Tan L., for OUCRU COVID-19 research group None.
We tested pre-pandemic (2015-2019) plasma samples from 148 Vietnamese children, and 100 Vietnamese adults at high risk of zoonotic infections, for antibodies against SARS-CoV-2 nucleocapsid and spike proteins. None was positive. The data thus demonstrated that there was no evidence of prior serological cross-reactivity with SARS-CoV-2 that might explain the low numbers of COVID-19 in Vietnam. Future studies should look at pre-existing B cell and T cell memory in pre-pandemic samples in Vietnam, which might further shed light on the pathogenesis of the infection.