Effectiveness of mRNA and inactivated COVID-19 vaccines: A test-negative study in an infection-naïve Hong Kong population - 10/07/23

Summary |
Objective |
Assess real-world effectiveness of vaccines against COVID-19.
Methods |
A test-negative study was conducted in January-May 2022 during an Omicron BA.2 wave in Hong Kong. COVID-19 was identified by RT-PCR. 1–1 case-control matching was based on propensity score with vaccine effectiveness adjusted for confounders.
Results |
Altogether, 1781 cases and 1737 controls aged 3–105 years were analysed. The mean lag time from the last dose of vaccination to testing for SARS-CoV-2 was 133.9 (SD: 84.4) days. Two doses of either vaccine within 180 days offered a low effectiveness against COVID-19 of all severity combined (VEadj [95% CI] for BNT162b2: 27.0% [4.2–44.5], CoronaVac: 22.9% [1.3–39.7]), and further decreased after 180 days. Two doses of CoronaVac were poorly protective 39.5% [4.9–62.5] against severe diseases for age ≥ 60 years, but the effectiveness increased substantially after the third dose (79.1% [25.7–96.7]). Two doses of BNT162b2 protected age ≥ 60 years against severe diseases (79.3% [47.2, 93.9]); however, the uptake was not high enough to assess three doses.
Conclusions |
The current real-world analysis indicates a high vaccine effectiveness of three doses of inactivated virus (CoronaVac) vaccines against Omicron variant, whereas the effectiveness of two doses is suboptimal.
Le texte complet de cet article est disponible en PDF.Highlights |
• | Vaccine effectiveness of 2 doses of BNT162b2 or CoronaVac decreased after 180 days. |
• | 3 rather than 2 doses of CoronaVac protected age ≥ 60 years against severe diseases. |
• | Effectiveness of both vaccines retained for people with multiple comorbidities. |
Keywords : COVID-19, SARS-CoV-2, Vaccine, Effectiveness, Comorbidity, Hong Kong, Chinese, BNT162b2, CoronaVac, Omicron
Plan
Vol 87 - N° 2
P. 136-143 - août 2023 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.