The impact of COVID-19 vaccination programme in the Republic of San Marino: Focus on effectiveness of Gam-Covid-Vac. (December 2022)

• Record Type: Journal Article
• Authors: Tonnara, Giuseppe; Piselli, Pierluca; Cimaglia, Claudia; Arlotti, Massimo; Sacchini, Elena; Manoni, Samanta; Zani, Antonio; Muccioli, Fausto; Laderchi, Anna; Rabini, Sergio; Antinori, Andrea; Vaia, Francesco; Nicastri, Emanuele; Girardi, Enrico
• Is Part Of: Clinical microbiology and infection. Volume 28:Number 12(2022)
• Page Start: 1636
• Page End: 1643
• Publication Date: 2022-12
• Subjects: COVID-19 -- Effectiveness -- Gam COVID-Vac -- SARS-CoV-2 -- Sputnik V -- Vaccination; Medical microbiology -- Periodicals; Diagnostic microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.01
• DOI: 10.1016/j.cmi.2022.06.026
• Languages: English
• ISSNs: 1198-743X

Abstract

Abstract: Objective: The adenovirus-based vaccine Gam-COVID-Vac (Sputnik V) showed promising effectiveness in a phase 3 clinical trial; however, data concerning its impact at a population level are scarce. The Republic of San Marino (RSM) conducted a SARS-CoV-2 vaccination programme mainly based (>80%) on Gam-COVID-Vac. Our aims were to investigate the impact of Gam-COVID-Vac vaccination programme and its effectiveness in a retrospective observational study based on the entire RSM population aged ≥12 years. Methods: We calculated the incidence rate and the vaccine effectiveness (VE) in the entire RSM population not previously infected, against SARS-CoV-2 infection and COVID-19–related hospitalization, from 25 February to 1 October 2021, considering any vaccine and separately according to the vaccine used. Vaccine effectiveness was calculated using a multivariable negative binomial regression model as 1-Incidence Rate Ratio. Results: During the study period, 21 568/28 791 (74.9%) not previously infected subjects received at least one dose of the Gam-COVID-Vac (84%) or BNT162b2, vaccines with 98% completing the vaccination schedule. Overall, 1634 SARS-CoV-2 infections and 166 COVID-19-related hospitalizations were observed with 17 COVID-19-related deaths reported. Incidence rates of SARS-CoV-2 infection and COVID-19-related hospitalization were 7.11 and 0.49/100 000 person-days in the fully vaccinated population, respectively. The adjusted overall VE was 67.6% (95% CI: 61.8–72.5) against SARS-CoV-2 infection and 87.9% (95% CI: 77.4–93.5) against COVID-19-related hospitalizations. Gam-COVID-Vac against SARS-CoV-2 infection VE peaked 91.8% (95% CI: 86.3–95.1) in the first bimester from the second dose, declining to 57.8% (95% CI: 42.2–69.2) at 6 months. Protection against hospitalization with COVID-19 was overall 91.6% (95% CI: 81.5–96.2), with no relevant waning trend over time. Discussion: Our study demonstrated the effectiveness of overall vaccination (Gam-COVID-Vac [84%] and BNT162b2 [16%]) in the prevention SARS-CoV-2 infection (pre- Omicron variant), waning over time but still with sustainable effectiveness against COVID-19-related hospitalization in the Republic of San Marino.