Impact of SARS‐CoV‐2 infection on vaccine‐induced immune responses over time

Abstract

Objective To determine the long‐term impact of prior SARS‐CoV‐2 infection on immune responses after COVID‐19 vaccination. Methods Using longitudinally collected blood samples from the COMMUNITY study, we determined binding (WHO BAU mL −1 ) and neutralising antibody titres against ten SARS‐CoV‐2 variants over 7 months following BNT162b2 in SARS‐CoV‐2‐recovered ( n = 118) and SARS‐CoV‐2‐naïve ( n = 289) healthcare workers with confirmed prior SARS‐CoV‐2 infection. A smaller group with ( n = 47) and without ( n = 60) confirmed prior SARS‐CoV‐2 infection receiving ChAdOx1 nCoV‐19 was followed for 3 months. SARS‐CoV‐2‐specific memory T‐cell responses were investigated in a subset of SARS‐CoV‐2‐naïve and SARS‐CoV‐2‐recovered vaccinees. Results Vaccination with both vaccine platforms resulted in substantially enhanced T‐cell responses, anti‐spike IgG responses and neutralising antibodies effective against ten SARS‐CoV‐2 variants in SARS‐CoV‐2‐recovered participants as compared to SARS‐CoV‐2‐naïve participants. The enhanced immune responses sustained over 7 months following vaccination. Conclusion These findings imply that prior SARS‐CoV‐2 infection should be taken into consideration when planning booster doses and design of current and future COVID‐19 vaccine programmes.

Seroprevalence of SARS-CoV-2 IgG Antibodies and Factors Associated with SARS-CoV-2 IgG Neutralizing Activity among Primary Health Care Workers 6 Months after Vaccination Rollout in France

“…The findings of this cross-sectional nationwide study, which included serum samples from 1612 PHCWs collected from June 2021 to August 2021, demonstrated a stronger immune response in PHCWs with a previous SARS-CoV-2 infection than those with no evidence of a previous SARS-CoV-2 infection, particularly PHCWs with a single vaccine dose. This is in line with previous studies [ 22 , 23 , 24 ] reporting higher and longer-lasting anti-S antibody levels among individuals with evidence of a previous SARS-CoV-2 infection than vaccinated individuals, which represents a remarkable and sustained enhancement of both the humoral and cellular responses, including higher neutralizing antibody responses [ 25 , 26 , 27 , 28 ]. As in previous studies [ 26 , 27 , 28 ], we show that PHCWs who experienced COVID-19 after a single dose of vaccine exhibited antibody titers similar to those that had received two doses of vaccine.…”

Immune responses after omicron infection in triple-vaccinated health-care workers with and without previous SARS-CoV-2 infection

“…It is possible that other factors are also involved in neutralisation, 6 which might be better reflected in live microneutralisation assays. However, when analysing a subset of samples we observed a strong correlation between live microneutralising titres and sVNT titres for both wildtype and BA.1 (appendix p 13), mirroring other reports 4,7 suggesting that sVNT can be used as a surrogate method for live virus neutralisation.…”

“…regularly assessed since April, 2020, in the ongoing Swedish COMMUNITY study. 3,4 For this sub-study, participants were screened with qPCR twice a week for 4 weeks, 5 with additional qPCR tests every other day for 14 days if positive. Blood samples were collected 1 week, 2 weeks, 3 weeks, 5 weeks, and 7 weeks after the first positive qPCR sample.…”

The Omicron wave and the waning of COVID-19 vaccine effectiveness. Influence of vaccine booster and age on confirmed infection incidence

“…However, the recommendation of a fourth dose is highly questionable. On one hand, the clinical presentation of COVID-19 is becoming milder, maybe due to vaccination programs, natural immunity achieved after infection [7] , hybrid immunity [8] or the debatable less virulence on new variants [9] . On the other hand, the protection against severe illness did not wane as fast as the protection against a confirmed infection, and a third doses could be enough to avoid severe cases of COVID-19.…”