Epidemiological and Serological Analysis of a SARS-CoV-2 Outbreak in a Nursing Home: Impact of SARS-CoV-2 Vaccination and Enhanced Neutralizing Immunity Following Breakthrough Infection

Abstract

Background: Despite a vaccination rate of 82.0% (n = 123/150), a SARS-CoV-2 (Alpha) outbreak with 64.7% (n = 97/150) confirmed infections occurred in a nursing home in Bavaria, Germany. Objective: the aim of this retrospective cohort study was to examine the effects of the Corminaty vaccine in a real-life outbreak situation and to obtain insights into the antibody response to both vaccination and breakthrough infection. Methods: the antibody status of 106 fully vaccinated individuals (54/106 breakthrough infections) and epidemiological data on all 150 residents and facility staff were evaluated. Results: SARS-CoV-2 infections (positive RT-qPCR) were detected in 56.9% (n = 70/123) of fully vaccinated, compared to 100% (n = 27/27) of incompletely or non-vaccinated individuals. The proportion of hospitalized and deceased was 4.1% (n = 5/123) among fully vaccinated and therewith lower compared to 18.5% (n = 5/27) hospitalized and 11.1% (n = 3/27) deceased among incompletely or non-vaccinated. Ct values were significantly lower in incompletely or non-vaccinated (p = 0.02). Neutralizing antibodies were detected in 99.1% (n = 105/106) of serum samples with significantly higher values (p < 0.001) being measured post-breakthrough infection. α-N-antibodies were detected in 37.7% of PCR positive but not in PCR negative individuals. Conclusion: Altogether, our data indicate that SARS-CoV-2 vaccination does provide protection against infection, severe disease progression and death with regards to the Alpha variant. Nonetheless, it also shows that infection and transmission are possible despite full vaccination. It further indicates that breakthrough infections can significantly enhance α-S- and neutralizing antibody responses, indicating a possible benefit from booster vaccinations.

SARS‐CoV‐2 immunoassays in a predominantly vaccinated population: Performances and qualitative agreements obtained with two analytical approaches and four immunoassays

“…With one exception (i.e., VITROS immunoassay), the observed sensitivities obtained with the conventional approach—and in a predominantly vaccinated population—were lower than those previously reported in unvaccinated populations (Table S3). This observation is consistent with the blunted anti‐N response in vaccinated individuals [3–7]. Notably, with samples collected ~1 month after a positive SARS‐CoV‐2 test result, none of the study immunoassays would meet Canada's regulatory requirement for sensitivity (i.e., ≥95% [11]) if these immunoassays were used in a vaccinated population and the results were analysed with the conventional approach using manufacturer‐recommended cutoffs.…”

“…However, blood services faced many challenges while conducting these serosurveys, including the fact that the anti-N response to an infection is often blunted and hardly detectable in recipients of a SARS-CoV-2 messenger ribonucleic acid (mRNA) vaccine [3][4][5][6][7]. This issue may be addressed in at least two ways.…”

Special Issue: Advances in SARS-CoV-2 Infection

“…A total of 15 manuscripts have been published in this Special Issue. These papers provided insights into epidemiology, pathogenesis, epigenetics [3,4] COVID-19 emergencies in hospital settings [5,6], advanced diagnosis [6][7][8], vaccination [9,10], and SARS-CoV-2 infection in the experimental setting [11]. The high scientific rigor, originality, and, for some of them, the high number of citations obtained, are well evident.…”

“…Finally, considering the emergence of new variants, especially from countries where there has not been much stratification of vaccination, how will the situation evolve in general? From the literature data, it appears that breakthrough infections can significantly enhance α-Sand neutralizing antibody responses, indicating a possible benefit from booster vaccinations [9,10,20]. It is not excluded that many of these questions may be answered in the second edition (2023) of this Special Issue.…”