Abstract
Objective: T-cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are observed in unexposed individuals. We evaluated the impact of this pre-existing cellular response on incident SARS-CoV-2 infections.
Methods: This was a follow-up study of 38 seronegative healthcare workers (HCWs) with previous evaluation of CD8+ and CD4+ T-cell responses after stimulation with SARS-CoV-2 structural proteins. Infection was considered in the presence of a positive RT-PCR test and/or confirmed seroconversion.
Results: Twenty of the 38 HCWs included (53%) had a previous specific CD8+ T-cell response to peptides encompassing the spike protein (S) in 13 (34%), the membrane (M) in 17 (45%), or/and the nucleocapsid (N) in three (8%). During a follow-up of 189 days (interquartile range (IQR) 172-195), 11 HCWs (29%) had an RT-PCR-positive test (n = 9) or seroconverted (n = 2). Median duration of symptoms was 2 days (IQR 0-7), and time to negative RT-PCR was 9 days (IQR 4-10). Notably, six incident infections (55%) occurred in HCWs with a pre-existing T-cell response (30% of those with a cellular response), who showed a significantly lower duration of symptoms (three were asymptomatic). Three of the six HCWs having a previous T-cell response continued to test seronegative. All the infected patients developed a robust T-cell response to different structural SARS-CoV-2 proteins, especially to protein S (91%).
Conclusion: A pre-existing T-cell response does not seem to reduce incident SARS-CoV-2 infections, but it may contribute to asymptomatic or mild disease, rapid viral clearance and differences in seroconversion.
Keywords: COVID-19; Cross-reactivity; Healthcare workers; Immune response; SARS-CoV-2; T-cell response.
【저자키워드】 COVID-19, SARS-CoV-2, immune response, Healthcare workers, T-cell Response, cross-reactivity, 【초록키워드】 coronavirus, immune response, Healthcare workers, T-cell Response, Infection, peptide, severe acute respiratory syndrome Coronavirus, RT-PCR, healthcare worker, viral clearance, Spike protein, Seroconversion, Viral, Asymptomatic, nucleocapsid, HCWs, response, peptides, Mild, membrane, structural proteins, Follow-up, respiratory, disease, SARS-CoV-2 infections, seronegative, protein S, T-cell responses, Stimulation, cellular response, positive RT-PCR, SARS-CoV-2 proteins, HCW, follow-up study, interquartile range, acute respiratory syndrome, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, CD8+, significantly lower, negative RT-PCR, CD4+ T-cell, robust, occurred, evaluated, seroconverted, contribute, the spike protein, infected patient, reduce, individuals, CD8+ T-cell, duration of symptom, IQR, pre-existing T-cell, 【제목키워드】 SARS CoV-2, Infection, prospective cohort study, healthcare worker, pre-existing T-cell,