Susceptibility to reinfection with SARS-CoV-2 virus relative to existing antibody concentrations and T cell response

• Published in: International journal of infectious diseases Vol. 131; pp. 100 - 110
• Main Authors: Atef, Shereen, Al Hosani, Farida, AbdelWareth, Laila, Al-Rifai, Rami H., Abuyadek, Rowan, Jabari, Andrea, Ali, Raghib, Altrabulsi, Basel, Dunachie, Susanna, Alatoom, Adnan, Donnelly, James G
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01-06-2023; The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases; Elsevier
• Subjects: Antibodies, Neutralizing; Antibodies, Viral; COVID-19; Humans; Immunoglobulin G; Neutralizing antibodies; Reinfection; Reinfection - epidemiology; SARS-CoV-2; SARS-CoV-2 immunocompetence; Seroepidemiologic Studies; Seroprevalence; Spike and receptor binding protein antibodies; T cell response; SARS-CoV-2 immunocompetence; Reinfection; Neutralizing antibodies; Spike and receptor binding protein antibodies; T cell response; Seroprevalence
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2023.01.006

•Living conditions affect the exposure to SARS-CoV-2 in vaccinated individuals.•T cell reactivity to SARS-CoV-2 wanes over time.•Reinfection of dormitory dwellers occurred as Omicron spread.•T cell reactivity greatly increased the protection from reinfection to SARS-CoV-2.•Elevated SARS-CoV-2 titers did not confer complete immunity.
We investigated the reinfection rate of vaccinated or convalescent immunized SARS-CoV-2 in 952 expatriate workers with SARS-CoV-2 serological antibody (Ab) patterns and surrogate T cell memory at recruitment and follow-up.
Trimeric spike, nucleocapsid, and neutralizing Abs were measured, along with a T cell stimulation assay, targeting SARS-CoV-2 memory in clusters of differentiation (CD) 4+ and CD8+ T cells. The subjects were then followed up for reinfection for up to 6 months.
The seroprevalence positivity at enrollment was greater than 99%. The T cell reactivity in this population was 38.2%. Of the 149 (15.9%) participants that were reinfected during the follow-up period (74.3%) had nonreactive T cells at enrollment. Those who had greater than 100 binding Ab units/ml increase from the median concentration of antispike immunoglobulin G Abs had a 6% reduction in the risk of infection. Those who were below the median concentration had a 78% greater risk of infection.
Significant immune protection from reinfection was observed in those who retained T cell activation memory. Additional protection was observed when the antispike was greater than the median value.