Susceptibility to Reinfection with SARS-CoV-2 Virus Relative to Existing Antibody Concentrations and T cell Response.
Atef S., Hosani FA., AbdelWareth L., Al-Rifai RH., Abuyadek R., Jabari A., Ali R., Altrabulsi B., Dunachie S., Alatoom A., Donnelly JG.
BACKGROUND: We have investigated the reinfection rate of vaccinated or convalescent immunized SARS-CoV-2 in 952 expatriate workers with SARS-CoV-2 serological antibody patterns and surrogate T cell memory at recruitment and follow up. METHODS: Trimeric spike, nucleocapsid, and neutralizing antibodies were measured along with a T cell stimulation assay targeting SARS-CoV-2 memory in CD4+ and CD8+ T cells. The subjects were then followed up for reinfection for up to six months. RESULTS: Seroprevalence positivity at enrollment was greater than 99%. T cell reactivity in this population was 38.2%. Of the 149 (15.9%) participants that were re-infected during the follow up period (74.3%) had nonreactive T cells at enrollment. Those who had greater than 100 BAU/mL increase from the median concentration of Anti-S IgG antibodies had a 6% reduction in the risk of infection. Those who were below the median concentration had a 78% greater risk of infection. CONCLUSIONS: Significant immune protection to reinfection was observed in those that retained T cell activation memory. Additional protection was observed when Anti-S was greater than the median value.