SARS-CoV-2 Infection in Fully Vaccinated Individuals of Old Age Strongly Boosts the Humoral Immune Response.

Lisa Müller,Florian Klein,Greta Flüh,Edwin Bölke,Andreas Walker,Philipp Niklas Ostermann,Nathalie Jazmati,Heiner Schaal,Hilmar Wisplinghoff,Eva Heger,Jörg Timm,Kanika Vanshylla,Marcel Andrée,Ortwin Adams,Ingo Drexler,Johannes C Fischer

doi:10.3389/fmed.2021.746644

Abstract

Prophylactic vaccination against SARS-CoV-2 is one of the most important measures to contain the COVID-19 pandemic. Recently, break-through infections following vaccination against this virus have been reported. Here, we describe the humoral immune response of break-through infections in fully vaccinated individuals of old age from an outbreak in a nursing home. In cooperation with the local health authority, blood samples from fully vaccinated and infected as well as fully vaccinated and uninfected residents of the nursing home were collected 4 weeks after the onset of the outbreak. The humoral immune response was determined in a neutralisation assay with replication-competent virus isolates and by a quantitative ELISA. In this outbreak a total of 23 residents and four health care workers were tested positive for SARS-CoV-2. Four residents were unvaccinated, including one with a severe course of disease who later severe disease course who later succumbed to infection. Despite their old age, all vaccinated residents showed no or only mild disease. Comparison of the humoral immune response revealed significantly higher antibody levels in fully vaccinated infected individuals compared to fully vaccinated uninfected individuals (p < 0.001). Notably, although only a minority of the vaccinated uninfected group showed neutralisation capacity against SARS-CoV-2, all vaccinated and infected individuals showed high-titre neutralisation of SARS-CoV-2 including the alpha and beta variant. Large SARS-CoV-2 outbreaks can occur in fully vaccinated populations, but seem to associate with mild disease. SARS-CoV-2 infection in fully vaccinated individuals is a strong booster of the humoral immune response providing enhanced neutralisation capacity against immune evasion variants.

Highlights

Prophylactic vaccination against SARS-CoV-2 is one of the most important measures to contain the COVID-19 pandemic [1,2,3,4,5]
To distinguish antibody responses induced by vaccination from those induced by SARS-CoV-2 infections, the SARS-CoV-2 IgG chemiluminescent microparticle immunoassay (CMIA) from Abbott was performed on an ARCHITECT i2000Abbott
SARS-CoV-2 infections after vaccination have been described in various reports and demonstrate that sustained sterile immunity against COVID-19 is not always achieved

Summary

INTRODUCTION

Prophylactic vaccination against SARS-CoV-2 is one of the most important measures to contain the COVID-19 pandemic [1,2,3,4,5]. Various studies have shown that in persons over 80 years of age, both humoral immunity and cellular immunity are weaker after vaccination against SARS-CoV-2 compared to younger control groups [13,14,15]. In collaboration with local public health authorities, the outbreak was investigated and all residents of the facility where the infections had occurred were offered voluntary blood donations for analysis of antiSARS-CoV-2 seroprevalence and humoral immune responses. To distinguish antibody responses induced by vaccination from those induced by SARS-CoV-2 infections, the SARS-CoV-2 IgG chemiluminescent microparticle immunoassay (CMIA) from Abbott was performed on an ARCHITECT i2000Abbott. For comparison of the groups, a one-way ANOVA (Kruskal-Wallis test) with Dunn’s correction for multiple comparisons was performed

RESULTS

DISCUSSION

ETHICS STATEMENT