SARS CoV-2 infections in healthcare workers with a pre-existing T-cell response: a prospective cohort study. (June 2021)

• Record Type: Journal Article
• Authors: Casado, José L.; Häemmerle, Johannes; Vizcarra, Pilar; Velasco, Hector; Velasco, Tamara; Fernandez-Escribano, Marina; Vallejo, Alejandro
• Is Part Of: Clinical microbiology and infection. Volume 27:Number 6(2021)
• Page Start: 916.e1
• Page End: 916.e4
• Publication Date: 2021-06
• Subjects: COVID-19 -- Cross-reactivity -- Healthcare workers -- Immune response -- SARS-CoV-2 -- T-cell response; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2021.02.020
• Languages: English
• ISSNs: 1198-743X

Abstract

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. Graphical abstract: Image 1