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Vaccine effectiveness in reducing COVID-19-related hospitalization after a risk-age-based mass vaccination program in a Chilean municipality: A comparison of observational study designs.
Urquidi, Cinthya; Sepúlveda-Peñaloza, Alejandro; Valenzuela, María T; Ponce, Alexander; Menares, Verónica; Cortes, Claudia P; Benítez, Rosana; Santelices, Emilio; Anfossi, Renato; Moller, Andrea; Santolaya, María E.
Afiliación
  • Urquidi C; Department of Epidemiology, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.
  • Sepúlveda-Peñaloza A; Department of Epidemiology, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.
  • Valenzuela MT; Department of Epidemiology, Faculty of Medicine, Universidad de Los Andes, Santiago, Chile.
  • Ponce A; Information Technology Services, Development Department, Universidad de O'Higgins, Rancagua, Chile.
  • Menares V; Hospital Regional Libertador Bernardo ÓHiggins, Rancagua, Chile.
  • Cortes CP; Department of Internal Medicine, Faculty of Medicine, Universidad de Chile, Santiago, Chile.
  • Benítez R; Infectious Diseases Department, Clínica Dávila, Santiago, Chile.
  • Santelices E; Policy and Innovation Center, Universidad de Desarrollo, Santiago, Chile.
  • Anfossi R; Hospital Regional Libertador Bernardo ÓHiggins, Rancagua, Chile.
  • Moller A; Hospital Regional Libertador Bernardo ÓHiggins, Rancagua, Chile.
  • Santolaya ME; Department of Pediatrics, Hospital Dr. Luis Calvo Mackenna, Faculty of Medicine, Universidad de Chile, Santiago, Chile. Electronic address: msantola@uchile.cl.
Vaccine ; 42(18): 3851-3856, 2024 Jul 11.
Article en En | MEDLINE | ID: mdl-38749822
ABSTRACT

BACKGROUND:

Case-control studies involving test-negative (TN) and syndrome-negative (SN) controls are reliable for evaluating influenza and rotavirus vaccine effectiveness (VE) during a random vaccination process. However, there is no empirical evidence regarding the impact in real-world mass vaccination campaigns against SARS-CoV-2 using TN and SN controls.

OBJECTIVE:

To compare in the same population the effectiveness of SARS-CoV-2 vaccination on COVID-19-related hospitalization rates across a cohort design, TN and SN designs.

METHOD:

We conducted an unmatched population-based cohort, TN and SN case-control designs linking data from four data sources (public primary healthcare system, hospitalization registers, epidemiological surveillance systems and the national immunization program) in a Chilean municipality (Rancagua) between March 1, 2021 and August 31, 2021. The outcome was COVID-19-related hospitalization. To ensure sufficient sample size in the unexposed group, completion of follow-up in the cohort design, and sufficient time between vaccination and hospitalization in the case-control design, VE was estimated comparing 8-week periods for each individual.

RESULTS:

Among the 191,505 individuals registered in the primary healthcare system of Rancagua in Chile on March 1, 2021; 116,453 met the cohort study's inclusion criteria. Of the 9,471 hospitalizations registered during the study period in the same place, 526 were COVID-19 cases, 108 were TN controls, and 1,628 were SN controls. For any vaccine product, the age- and sex-adjusted vaccine effectiveness comparing fully and nonvaccinated individuals was 67.2 (55.7-76.3) in the cohort design, whereas it was 67.8 (44.1-81.4) and 77.9 (70.2-83.8) in the TN and SN control designs, respectively.

CONCLUSION:

The VE of a COVID-19 vaccination program based on age and risk groups tended to differ across the three observational study designs. The SN case-control design may be an efficient option for evaluating COVID-19 VE in real-world settings.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Vacunación Masiva / Vacunas contra la COVID-19 / SARS-CoV-2 / COVID-19 / Eficacia de las Vacunas / Hospitalización Límite: Adolescent / Adult / Aged / Aged80 / Child / Child, preschool / Female / Humans / Infant / Male País/Región como asunto: America do sul / Chile Idioma: En Revista: Vaccine Año: 2024 Tipo del documento: Article País de afiliación: Chile Pais de publicación: Países Bajos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Vacunación Masiva / Vacunas contra la COVID-19 / SARS-CoV-2 / COVID-19 / Eficacia de las Vacunas / Hospitalización Límite: Adolescent / Adult / Aged / Aged80 / Child / Child, preschool / Female / Humans / Infant / Male País/Región como asunto: America do sul / Chile Idioma: En Revista: Vaccine Año: 2024 Tipo del documento: Article País de afiliación: Chile Pais de publicación: Países Bajos