Robust SARS-CoV-2-specific T-cell immunity is maintained at 6 months following primary infection

Zuo, Jianmin; Dowell, Alexander C.; Pearce, Hayden; Verma, Kriti; Long, Heather M.; Begum, Jusnara; Aiano, Felicity; Amin-Chowdhury, Zahin; Hallis, Bassam; Stapley, Lorrain; Borrow, Ray; Linley, Ezra; Ahmad, Shazaad; Parker, Ben; Horsley, Alex; Amirthalingam, Gayatri; Brown, Kevin; Ramsay, Mary E.; Ladhani, Shamez; Moss, Paul

The immune response to SARS-CoV-2 is critical in controlling disease but there is concern that waning immunity may predispose to re-infection. We analysed the magnitude and phenotype of the SARS-CoV-2-specific T cell response in 100 donors at six months following infection. T-cell responses were present by ELISPOT and/or ICS analysis in all donors and characterised by predominant CD4+ T cell responses with strong IL-2 cytokine expression. Median T-cell responses were 50% higher in donors who had experienced a symptomatic infection indicating that the severity of primary infection establishes a ‘setpoint’ for cellular immunity. T-cell responses to spike and nucleoprotein/membrane proteins were correlated with peak antibody levels. Furthermore, higher levels of nucleoprotein-specific T cells were associated with preservation of NP-specific antibody level although no such correlation was observed in relation to spike-specific responses. In conclusion, our data are reassuring that functional SARS-CoV-2-specific T-cell responses are retained at six months following infection.