Effectiveness of COVID-19 vaccine booster in the general population and in subjects with comorbidities. A population-based study in Spain
Narmeen Mallah, Jacobo Pardo‐Seco, Luis‐Ricardo López‐Pérez, Juan‐Manuel González‐Pérez, Benigno Rosón, María‐Teresa Otero‐Barrós, Carmen Durán‐Parrondo, Victoria Nartallo‐Penas, Susana Mirás‐Carballal, Carmen Rodríguez‐Tenreiro, Irene Rivero‐Calle, Alberto Gómez‐Carballa, Antonio Salas, Federico Martinón‐Torres
Abstract
BACKGROUND: 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. METHOD: 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. RESULTS: = 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. CONCLUSIONS: 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.