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Antibody response to SARS‐CoV‐2 vaccination is extremely vivacious in subjects with previous SARS‐CoV‐2 infection
Author(s) -
Callegaro Annapaola,
Borleri Daniela,
Farina Claudio,
Napolitano Gavino,
Valenti Daniela,
Rizzi Marco,
Maggiolo Franco
Publication year - 2021
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.26982
Subject(s) - medicine , interquartile range , vaccination , asymptomatic , confidence interval , titer , covid-19 , antibody , virology , coronavirus , immunology , antibody titer , disease , infectious disease (medical specialty)
The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) pandemic calls for rapid actions, now principally oriented to a world‐wide vaccination campaign. In this study we verified if, in individuals with a previous SARS‐CoV‐2 infection, a single dose of messenger RNA (mRNA) vaccine would be immunologically equivalent to a full vaccine schedule in naïve individuals. Health care workers (184) with a previous SARS‐CoV‐2 infection were sampled soon before the second dose of vaccine and between 7 and 10 days after the second dose, the last sampling time was applied to SARS‐CoV‐2 naïve individuals, too. Antibodies against SARS‐CoV‐2 were measured using Elecsys Anti‐SARS‐CoV‐2 S immunoassay. The study was powered for non‐inferiority. We used non parametric tests and Pearson correlation test to perform inferential analysis. After a single vaccine injection, the median titer of specific antibodies in individuals with previous coronavirus disease 2019 was 30.527 U/ml (interquartile range [IQR]: 19.992–39.288) and in subjects with previous SARS‐CoV‐2 asymptomatic infection was 19.367.5 U/ml (IQR: 14.688–31.353) ( p = .032). Both results were far above the median titer in naïve individuals after a full vaccination schedule: 1974.5 U/ml (IQR: 895–3455) ( p < .0001). Adverse events after vaccine injection were more frequent after the second dose of vaccine (mean: 0.95; 95% confidence interval [CI]: 0.75–1.14 vs. mean: 1.91; 95% CI: 1.63–2.19) ( p < .0001) and in exposed compared to naïve (mean: 1.63; 95% CI: 1.28–1.98 vs. mean: 2.35; 95% CI: 1.87–2.82) ( p = .015). In SARS‐CoV‐2 naturally infected individuals a single mRNA vaccine dose seems sufficient to reach immunity. Modifying current dosing schedules would speed‐up vaccination campaigns.