Successful clearance of persistent SARS-CoV-2 asymptomatic infection following a single dose of Ad5-nCoV vaccine

Persistent asymptomatic(PA)SARS-CoV-2 infections have been identified.The immune responses in these patients are unclear,and the development of effective treatments for these patients is needed.Here,we report a cohort of 23 PA cases carrying viral RNA for up to 191 days.PA cases displayed low levels of inflammatory and interferon response,weak antibody response,diminished circulating follicular helper T cells(cTfh),and inadequate specific CD4+and CD8+T-cell responses during infection,which is distinct from symptomatic infections and resembling impaired immune activation.Administration of a single dose of Ad5-nCoV vaccine to 10 of these PA cases elicited rapid and robust antibody responses as well as coordinated B-cell and cTfh responses,resulting in successful viral clearance.Vaccine-induced antibodies were able to neutralize various variants of concern and persisted for over 6 months,indicating long-term protection.Therefore,our study provides an insight into the immune status of PA infections and highlights vaccination as a potential treatment for prolonged SARS-CoV-2 infections.