Population-Level Effectiveness of an Inactivated Whole-Virion COVID-19 Vaccine: A Test Negative Case-Control Study in the Dominican Republic. (14th February 2023)

• Record Type: Journal Article
• Authors: Pérez-Then, Eddy; Miric, Marija; Qian, Han-Zhu; Chen, Ying Qing; Wang, Yixin; Vallejo, Virginia; Quezada, Wanda; Flaquer, Melissa; Olivo, Juan; Castillo, Jean; García, Natalia; Calderón, Katherine; Cueto, Scarlet; Veras, Bienvenido; Russo, Miguel; Jiménez, Indira; Guzmán, Sorileydi; Garabito, Luz; Cueto, Evelyn; Colombo, Fátima; Taveras, Dominga; Torres, Dania; Baez, Jeannette; Yunen, Jose; Koenig, Ellen; Pérez, Eladio; López, Oscar; Severino Medina, Fior Estephanie; Wang, Xuanyi; Shao, Yiming; Vermund, Sten H;
• Is Part Of: Open forum infectious diseases. Volume 10:Number 3(2023)
• Publication Date: 2023-02-14
• Subjects: COVID-19 -- Dominican Republic -- SARS-CoV-2 -- test-negative case-control study -- vaccine effectiveness; Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofad075
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: A continuing nationwide vaccination campaign began in the Dominican Republic on February 16, 2021 to prevent severe consequences of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Estimates of vaccine effectiveness under real-world conditions are needed to support policy decision making and inform further vaccine selection. Methods: We conducted a test-negative case-control study to assess the real-world effectiveness of nationwide coronavirus disease 2019 (COVID-19) vaccination program using an inactivated vaccine (CoronaVac) on preventing symptomatic SARS-CoV-2 infections and hospitalizations from August to November 2021 in the Dominican Republic. Participants were recruited from 10 hospitals in 5 provinces to estimate the effectiveness of full immunization (≥14 days after receipt of the second dose) and partial immunization (otherwise with at least 1 dose ≥14 days after receipt of the first dose). Results: Of 1078 adult participants seeking medical care for COVID-19-related symptoms, 395 (36.6%) had positive polymerase chain reaction (PCR) tests for SARS-CoV-2; 142 (13.2%) were hospitalized during 15 days of follow up, including 91 (23%) among 395 PCR-positive and 51 (7.5%) among 683 PCR-negative participants. Full vaccination was associated with 31% lower odds of symptomatic infection (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.52–0.93) and partial vaccination was associated with 49% lower odds (OR, 0.51; CI, 0.30–0.86). Among 395 PCR-positive participants, full vaccination reduced the odds of COVID-19-related hospitalization by 85% (OR, 0.15; 95% CI, 0.08–0.25) and partial vaccination reduced it by 75% (OR, 0.25; 95% CI, 0.08–0.80); full vaccination was associated with reduced use of assisted ventilation by 73% (OR, 0.27; 95% CI, 0.15–0.49). Conclusions: Given the ancestral and delta viral variants circulating during this study period, our results suggest that the inactivated COVID-19 vaccine offered moderate protection against symptomatic SARS-CoV-2 infections and high protection against COVID-19-related hospitalizations and assisted ventilation. This is reassuring given that, as of August 2022, an estimated 2.6 billion inactivated CoronaVac vaccine doses had been administered worldwide. This vaccine will become a basis for developing multivalent vaccine against the currently circulating omicron variant. Abstract : This test-negative case-control study among 1078 adult participants seeking healthcare for COVID-19-related symptoms showed that inactivated whole-virion vaccine offered moderate protection against symptomatic SARS-CoV-2 infection. The inactivated vaccine offered high protection against COVID-19-related hospitalization and reduced use of assisted ventilation.