TY - JOUR
T1 - Effect of vaccination on SARS-CoV-2 reinfection risk:a case–control study in the Republic of Cyprus
AU - Quattrocchi, Annalisa
AU - Tsioutis, Constantinos
AU - Demetriou, Anna
AU - Kyprianou, Theopisti
AU - Athanasiadou, Maria
AU - Silvestros, Valentinos
AU - Mamais, Ioannis
AU - Demetriou, Christiana A.
AU - Theophanous, Fani
AU - Soteriou, Soteroulla
AU - Gregoriadou, Chryso
AU - Anastasiou, Eleni
AU - Kolios, Panayiotis
AU - Ηaralambous, Christos
AU - Gregoriou, Ioanna
AU - Kalakouta, Olga
AU - Nikolopoulos, Georgios
N1 - Publisher Copyright:
© 2022 The Royal Society for Public Health
PY - 2022/3
Y1 - 2022/3
N2 - Objectives: We explored the effectiveness of COVID-19 vaccines in preventing reinfection in the Republic of Cyprus. Study design: This was a matched case–control study (1:2). Methods: Cases were adults with a first episode of SARS-CoV-2 infection in 2020 and a second episode (i.e. reinfection) between June and August 2021. Controls were adults with only one infection episode in 2020 (i.e. not reinfected). Matching was performed by age, gender, and week of diagnosis for the first episode. The reinfection date of a case was applied to the matched controls for estimating full or partial vaccination status. Cases and controls were classified as unvaccinated, partially vaccinated (i.e. vaccination series not completed or final dose received ≤14 days before the reinfection date), or fully vaccinated (i.e. final dose received >14 days before the reinfection date). Conditional logistic regression was performed to calculate odds ratios and 95% confidence intervals for full or partial vaccination, against no vaccination, between controls and cases. Results: This study showed that controls were more likely to be vaccinated (odds ratio for full vaccination: 5.51, 95% confidence interval: 2.43–12.49) than cases. Conclusions: This finding answers a pressing question of the public and supports the offer of vaccination to people with previous SARS-CoV-2 infection.
AB - Objectives: We explored the effectiveness of COVID-19 vaccines in preventing reinfection in the Republic of Cyprus. Study design: This was a matched case–control study (1:2). Methods: Cases were adults with a first episode of SARS-CoV-2 infection in 2020 and a second episode (i.e. reinfection) between June and August 2021. Controls were adults with only one infection episode in 2020 (i.e. not reinfected). Matching was performed by age, gender, and week of diagnosis for the first episode. The reinfection date of a case was applied to the matched controls for estimating full or partial vaccination status. Cases and controls were classified as unvaccinated, partially vaccinated (i.e. vaccination series not completed or final dose received ≤14 days before the reinfection date), or fully vaccinated (i.e. final dose received >14 days before the reinfection date). Conditional logistic regression was performed to calculate odds ratios and 95% confidence intervals for full or partial vaccination, against no vaccination, between controls and cases. Results: This study showed that controls were more likely to be vaccinated (odds ratio for full vaccination: 5.51, 95% confidence interval: 2.43–12.49) than cases. Conclusions: This finding answers a pressing question of the public and supports the offer of vaccination to people with previous SARS-CoV-2 infection.
KW - COVID-19
KW - Reinfection
KW - Vaccination
UR - http://www.scopus.com/inward/record.url?scp=85124710257&partnerID=8YFLogxK
U2 - 10.1016/j.puhe.2022.01.008
DO - 10.1016/j.puhe.2022.01.008
M3 - Article
C2 - 35193032
AN - SCOPUS:85124710257
SN - 0033-3506
VL - 204
SP - 84
EP - 86
JO - Public Health
JF - Public Health
ER -
