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. 2022 Sep 20:2:944820.
doi: 10.3389/fepid.2022.944820. eCollection 2022.

Detection of anti-SARS-CoV-2-Spike/RBD antibodies in vaccinated elderly from residential care facilities in Romania, April 2021

Teodora Vremera  1   2 , Florentina Ligia Furtunescu  2   3 , Mihaela Leustean  4 , Alexandru Rafila  3 , Adina David  4 , Iuliana Radu  4 , Ana Maria Cornienco  4 , Adina Gatea  4 , Ciprian Ilie  4 , Luminita Smaranda Iancu  5   6 , Adriana Pistol  2   3
Affiliations

Detection of anti-SARS-CoV-2-Spike/RBD antibodies in vaccinated elderly from residential care facilities in Romania, April 2021

Teodora Vremera et al. Front Epidemiol. .

Abstract

Introduction: SARS-CoV-2 infection rates and related mortality in elderly from residential care facilities are high. The aim of this study was to explore the immune status after COVID-19 vaccination in people 65 years and older.

Methods: The study involved volunteer participants living in residential care facilities. The level of anti-Spike/RBD antibodies was measured at 2-12 weeks after complete vaccination, using chemiluminescent microparticle immunoassay (SARS-CoV-2 IgG II Quant Abbott).

Results: We have analyzed 635 serum samples collected from volunteers living in 21 Residential Care Facilities. With one exception, in which the vaccination was done with the Moderna vaccine, all volunteers received the Pfizer-Comirnaty vaccine. Individuals enrolled in the study had ages between 65-110 years (median 79 years). Of the people tested, 54.8% reported at least one comorbidity and 59.2% reported having had COVID-19 before vaccination. The presence of anti-S/RBD antibodies at a protective level was detected in 98.7% of those tested (n = 627 persons) with a wide variation of antibody levels, from 7.1 to 5,680 BAU/ml (median 1287 BAU/ml). Antibody levels appeared to be significantly correlated to previous infection (r = 0.302, p = 0.000).

Conclusions: The study revealed the presence of anti-SARS CoV-2 antibodies in a significant percentage of those tested (98.7%). Of these, more than half had high antibody levels. Pre-vaccination COVID-19 was the only factor found to be associated with higher anti-S/RBD levels. The significant response in elderly people, even in those with comorbidities, supports the vaccination measure for this category, irrespective of associated disabilities or previous infection.

Keywords: COVID-19; SARS-CoV-2 infection; anti-Spike/RBD IgG; antibody; elderly; residential care facility.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Distribution of the patients with and without previous COVID-19 infections in the five groups of anti-S/RBD antibody levels, Romania, April 2021.
Figure 2
Figure 2
Distribution of the patients with and without associated pathologies in the five groups of anti-S/RBD antibody levels, Romania, April 2021.
See this image and copyright information in PMC

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