Effectiveness of the autumnal COVID-19 vaccine dose during the winter and summer waves of the 2023/24 season in Spain
Year: 2025
Type: article
Study design: Observational Study
Abstract: BACKGROUND: We estimated vaccine effectiveness (VE) of the COVID-19 monovalent XBB.1.5 vaccine recommended in Spain in October 2023 for ≥60-year-olds against medically attended COVID-19 and COVID-19 hospitalization, during winter and summer epidemic waves. RESEARCH DESIGN AND METHODS: Patients ≥60-year-olds consulting in primary-care or requiring hospitalization due to respiratory infection were systematically RT-PCR tested for SARS-CoV-2 and classified as cases if PCR-positive or controls if PCR-negative. Logistic regression compared autumnal vaccination ≥14 days before onset in cases and controls adjusting for sex, age group, comorbidities, region in Spain and week; VE=(1-Odds Ratio)x100. RESULTS: We included 1,141/3,286 and 1,386/5,260 cases/controls from primary-care and hospitals. During the winter wave, VE (95% Confidence Interval) was 28% (5;47%) against medically attended COVID-19 [45% (-31;80%) during XBB.1.5 dominance; 26% (-2;46%) during BA.2.86] and 39% (24;51%) against hospitalization [73% (41;89%) during XBB.1.5; 37% (17;48%) during BA.2.86]. During the summer wave, VE decreased; -6% (-33;15%) against infection [21% (-11;44%) during BA.2.86; -39% (-91;-1%) during KP.3] and 6% (-14;22%) against hospitalization [8% (-20;30%) during BA.2.86; 5% (-35;21%) during KP.3]. CONCLUSIONS: COVID-19 VE was moderate during the 2023/24 winter wave, higher during XBB.1.5 dominance and against hospitalization. Effectiveness was null during the summer wave, likely reflecting waning immunity and SARS-CoV-2 variant substitution.
Source: Expert Review of Vaccines
Authors: Ayelén Rojas-Benedicto, Gloria Pérez-Gimeno, Jacobo Mendioroz, Irene Pedrosa Corral, Miriam López Torrijos, Mercedes Rumayor, Mª Angeles Rafael de la Cruz Lopez, Eva Rivas Wagner, MªÁngel Valcárcel de Laiglesia, Inés Guiu Cañete, Ana Fernández Ibañez, Olaia Pérez Martínez, Juan Antonio Linares Dópido, Pello Latasa, Marta Torres-Juan, Mª Jesús Rodríguez Recio, Daniel Castrillejo, Luis Javier Viloria Raymundo, Ninoska López Berrios, Sonia Vázquez-Morón, Susana Monge
Institutions: Universidad Nacional de Educación a Distancia, Instituto de Salud Carlos III, Centro Nacional de Epidemiología, Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública, Agència de Salut Pública de Catalunya, Hospital Universitario Virgen de las Nieves, Generalitat Valenciana, Instituto Murciano de Investigación Biosanitaria, Gobierno del Principado de Asturias, Government of Extremadura, Centro de Investigación Biomédica en Red Enfermedades Infecciosas
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4415302377