Robust humoral and cellular immune responses and low risk for reinfection at least 8 months following asymptomatic to mild COVID-19.

Havervall S, Ng H, Jernbom Falk A, Greilert-Norin N, Månberg A, Marking U, Laurén I, Gabrielsson L, Salomonsson AC, Aguilera K, Kihlgren M, Månsson M, Rosell A, Hellström C, Andersson E, Olofsson J, Skoglund L, Yousef J, Pin E, Lord M, Åberg M, Hedhammar M, Tegel H, Dönnes P, Phillipson M, Nilsson P, Klingström J, Mangsbo S, Hober S, Thålin C

J Intern Med 291 (1) 72-80 [2022-01-00; online 2021-09-27]

Emerging data support detectable immune responses for months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, but it is not yet established to what degree and for how long protection against reinfection lasts. We investigated SARS-CoV-2-specific humoral and cellular immune responses more than 8 months post-asymptomatic, mild and severe infection in a cohort of 1884 healthcare workers (HCW) and 51 hospitalized COVID-19 patients. Possible protection against SARS-CoV-2 reinfection was analyzed by a weekly 3-month polymerase chain reaction (PCR) screening of 252 HCW that had seroconverted 7 months prior to start of screening and 48 HCW that had remained seronegative at multiple time points. All COVID-19 patients and 96% (355/370) of HCW who were anti-spike IgG positive at inclusion remained anti-spike IgG positive at the 8-month follow-up. Circulating SARS-CoV-2-specific memory T cell responses were detected in 88% (45/51) of COVID-19 patients and in 63% (233/370) of seropositive HCW. The cumulative incidence of PCR-confirmed SARS-CoV-2 infection was 1% (3/252) among anti-spike IgG positive HCW (0.13 cases per 100 weeks at risk) compared to 23% (11/48) among anti-spike IgG negative HCW (2.78 cases per 100 weeks at risk), resulting in a protective effect of 95.2% (95% CI 81.9%-99.1%). The vast majority of anti-spike IgG positive individuals remain anti-spike IgG positive for at least 8 months regardless of initial COVID-19 disease severity. The presence of anti-spike IgG antibodies is associated with a substantially reduced risk of reinfection up to 9 months following asymptomatic to mild COVID-19.

Category: Biochemistry

Category: Health

Funder: KAW/SciLifeLab

Research Area: Biobanks for COVID-19 research

Research Area: Drug discovery and repurposing of drugs

Research Area: High-throughput and high-content serology

Research Area: Host cell systems biology and targets

Research Area: Viral sequence evolution

PubMed 34459525

DOI 10.1111/joim.13387

Crossref 10.1111/joim.13387

pmc: PMC8661920

Publications 9.5.0