Effectiveness of COVID-19 vaccine booster in the general population and in subjects with comorbidities. A population-based study in Spain

• Published in: Environmental research Vol. 215; no. Pt 2; p. 114252
• Main Authors: Mallah, Narmeen, Pardo-Seco, Jacobo, López-Pérez, Luis-Ricardo, González-Pérez, Juan-Manuel, Rosón, Benigno, Otero-Barrós, María-Teresa, Durán-Parrondo, Carmen, Nartallo-Penas, Victoria, Mirás-Carballal, Susana, Rodríguez-Tenreiro, Carmen, Rivero-Calle, Irene, Gómez-Carballa, Alberto, Salas, Antonio, Martinón-Torres, Federico
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.12.2022; The Authors. Published by Elsevier Inc
• Subjects: Aged; Comorbidities; confidence interval; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 booster vaccine effectiveness; COVID-19 infection; COVID-19 Vaccines; diabetes; Humans; hypertension; Immunization, Secondary; mortality; obesity; Population-based study; regression analysis; respiratory tract diseases; Retrospective Studies; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Spain; Spain - epidemiology; vaccination; vaccines; Spain; Population-based study; SARS-CoV-2; COVID-19 booster vaccine effectiveness; Comorbidities; Spain
• ISSN: 0013-9351; 1096-0953; 1096-0953
• DOI: 10.1016/j.envres.2022.114252

Research on the effectiveness of COVID-19 booster-based vaccine schedule is ongoing and real-world data on vaccine effectiveness (VE) in comorbid patients are limited. We aimed to estimate booster dose VE against SARS-CoV-2 infection and COVID-19 severity in the general population and in comorbid patients. A retrospective test-negative control study was undertaken in Galicia-Spain (December 2020–November 2021). VE and 95% confidence interval (CI) were estimated using multivariate logistic regression models. 1,512,415 (94.13%) negative and 94,334 (5.87%) positive SARS-CoV-2 test results were included. A booster dose of COVID-19 vaccine is associated with substantially higher protection against SARS-CoV-2 infection than vaccination without a booster [VEboosted = 87% (95%CI: 83%; 89%); VEnon-boosted = 66% (95%CI: 65%; 67%)]. The high VE was observed in all ages, but was more pronounced in subjects older than 65 years. VE against COVID-19 severity was analyzed in a mixed population of boosted and non-boosted individuals and considerable protection was obtained [VE: hospitalization = 72% (95%CI: 68%; 75%); intensive care unit administration = 83% (95%CI: 78%; 88%), in-hospital mortality = 66% (95%CI: 53%; 75%)]. Boosted comorbid patients are more protected against SARS-CoV-2 infection than those who were non-boosted. This was observed in a wide range of major diseases including cancer (81% versus 54%), chronic obstructive pulmonary disease (84% versus 61%), diabetes (84% versus 65%), hypertension (82% versus 65%) and obesity (91% versus 67%), among others. A booster dose of COVID-19 vaccine increases the protection against SARS-CoV-2 infection and COVID-19 severity in the general population and in comorbid patients.