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Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers

We evaluated the clinical protection of BNT162b2 mRNA vaccine in healthcare workers (HCWs) and how COVID-19 manifestations and contagiousness change as the time since first dose increases. A matched (1:2 ratio) parallel cohort study was performed. During the first three months of vaccination campaig...

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Autores principales: Trunfio, Mattia, Verga, Federica, Ghisetti, Valeria, Burdino, Elisa, Emanuele, Teresa, Bonora, Stefano, Di Perri, Giovanni, Calcagno, Andrea
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8705309/
https://www.ncbi.nlm.nih.gov/pubmed/34960123
http://dx.doi.org/10.3390/vaccines9121377
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author Trunfio, Mattia
Verga, Federica
Ghisetti, Valeria
Burdino, Elisa
Emanuele, Teresa
Bonora, Stefano
Di Perri, Giovanni
Calcagno, Andrea
author_facet Trunfio, Mattia
Verga, Federica
Ghisetti, Valeria
Burdino, Elisa
Emanuele, Teresa
Bonora, Stefano
Di Perri, Giovanni
Calcagno, Andrea
author_sort Trunfio, Mattia
collection PubMed
description We evaluated the clinical protection of BNT162b2 mRNA vaccine in healthcare workers (HCWs) and how COVID-19 manifestations and contagiousness change as the time since first dose increases. A matched (1:2 ratio) parallel cohort study was performed. During the first three months of vaccination campaign, HCWs of the entire health district ASL Città di Torino (Turin, Italy) were classified according to SARS-CoV-2-positivity in respect of the vaccination schedule: post-first-dose (fHCWs, <12 days), partially (PHCWs, ≥12 from first dose to ≤7 days after the second), and totally vaccinated (THCWs, ≥8 days after the second dose). Age-/sex-matched unvaccinated controls were randomly selected from all the SARS-CoV-2-positivity detected in the same district and period. Previous infections were excluded. Clinical and virologic data (ORF1ab gene cycle threshold values, Ct) were recorded. In total, 6800 HCWs received at least one dose, and 55 tested positive subsequently: 20 fHCWs, 25 PHCWs, 10 THCWs. Furthermore, 21.8% of breakthrough infections were in male, with a median age of 49 years (32–56), and 51.4% occurred while SARS-CoV-2 B.1.1.7 variant was predominant. The incident relative risk was 0.13 (0.12–0.15) for PHCWs and 0.06 (0.05–0.07) for THCWs. Compared to controls (n = 110), no difference was observed in fHCWs, while PHCWs and THCWs showed higher prevalence of asymptomatic infections, fewer signs/symptoms with a milder systemic involvement, and significantly higher Ct values (PHCWs 30.3 (24.1–35.5) vs. 22.3 (19.6–30.6), p = 0.023; THCWs 35.0 (31.3–35.9) vs. 22.5 (18.2–30.6), p = 0.024). Duration of symptoms was also shorter in THCWs (5 days (3–6) vs. 9 (7–14), p = 0.028). A linear increase of 3.81 points in Ct values was observed across the groups by vaccination status (p = 0.001) after adjusting for age, sex, comorbidities, and time between COVID-19 onset and swab collection. BNT162b2 decreased the risk of PCR-confirmed infections and severe disease, and was associated with a virologic picture of lesser epidemiologic concern as soon as 12 days after the first vaccine dose.
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spelling pubmed-87053092021-12-25 Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers Trunfio, Mattia Verga, Federica Ghisetti, Valeria Burdino, Elisa Emanuele, Teresa Bonora, Stefano Di Perri, Giovanni Calcagno, Andrea Vaccines (Basel) Article We evaluated the clinical protection of BNT162b2 mRNA vaccine in healthcare workers (HCWs) and how COVID-19 manifestations and contagiousness change as the time since first dose increases. A matched (1:2 ratio) parallel cohort study was performed. During the first three months of vaccination campaign, HCWs of the entire health district ASL Città di Torino (Turin, Italy) were classified according to SARS-CoV-2-positivity in respect of the vaccination schedule: post-first-dose (fHCWs, <12 days), partially (PHCWs, ≥12 from first dose to ≤7 days after the second), and totally vaccinated (THCWs, ≥8 days after the second dose). Age-/sex-matched unvaccinated controls were randomly selected from all the SARS-CoV-2-positivity detected in the same district and period. Previous infections were excluded. Clinical and virologic data (ORF1ab gene cycle threshold values, Ct) were recorded. In total, 6800 HCWs received at least one dose, and 55 tested positive subsequently: 20 fHCWs, 25 PHCWs, 10 THCWs. Furthermore, 21.8% of breakthrough infections were in male, with a median age of 49 years (32–56), and 51.4% occurred while SARS-CoV-2 B.1.1.7 variant was predominant. The incident relative risk was 0.13 (0.12–0.15) for PHCWs and 0.06 (0.05–0.07) for THCWs. Compared to controls (n = 110), no difference was observed in fHCWs, while PHCWs and THCWs showed higher prevalence of asymptomatic infections, fewer signs/symptoms with a milder systemic involvement, and significantly higher Ct values (PHCWs 30.3 (24.1–35.5) vs. 22.3 (19.6–30.6), p = 0.023; THCWs 35.0 (31.3–35.9) vs. 22.5 (18.2–30.6), p = 0.024). Duration of symptoms was also shorter in THCWs (5 days (3–6) vs. 9 (7–14), p = 0.028). A linear increase of 3.81 points in Ct values was observed across the groups by vaccination status (p = 0.001) after adjusting for age, sex, comorbidities, and time between COVID-19 onset and swab collection. BNT162b2 decreased the risk of PCR-confirmed infections and severe disease, and was associated with a virologic picture of lesser epidemiologic concern as soon as 12 days after the first vaccine dose. MDPI 2021-11-23 /pmc/articles/PMC8705309/ /pubmed/34960123 http://dx.doi.org/10.3390/vaccines9121377 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Trunfio, Mattia
Verga, Federica
Ghisetti, Valeria
Burdino, Elisa
Emanuele, Teresa
Bonora, Stefano
Di Perri, Giovanni
Calcagno, Andrea
Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title_full Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title_fullStr Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title_full_unstemmed Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title_short Clinical Phenotype and Contagiousness of Early Breakthrough SARS-CoV-2 Infections after BNT162b2 COVID-19 mRNA Vaccine: A Parallel Cohort Study in Healthcare Workers
title_sort clinical phenotype and contagiousness of early breakthrough sars-cov-2 infections after bnt162b2 covid-19 mrna vaccine: a parallel cohort study in healthcare workers
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8705309/
https://www.ncbi.nlm.nih.gov/pubmed/34960123
http://dx.doi.org/10.3390/vaccines9121377
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