COVID-19 Vaccine Effectiveness in Autumn and Winter 2022 to 2023 Among Older Europeans
Authors: Laniece Delaunay Charlotte , Mazagatos Clara , Martínez-Baz Iván , Túri Gergő , Goerlitz Luise , Domegan Lisa , Meijer Adam , Rodrigues Ana Paula , Sève Noémie , Ilić Maja , Latorre-Margalef Neus , Lazar Mihaela , Maurel Marine , Melo Aryse , Andreu Ivorra Blanca , Casado Itziar , Horváth Judit Krisztina , Buda Silke , Bennett Charlene , de Lange Marit , Guiomar Raquel , Enouf Vincent , Mlinarić Ivan , Samuelsson Hagey Tove , Dinu Sorin , Rumayor Mercedes , Castilla Jesús , Oroszi Beatrix , Dürrwald Ralf , O’Donnell Joan , Hooiveld Mariëtte , Gomez Verónica , Falchi Alessandra , Kurečić Filipović Sanja , Dillner Lena , Popescu Rodica , Bacci Sabrina , Kaczmarek Marlena , Kissling Esther , Gallardo García Virtudes , Perez Morilla Esteban , Pedrosa Corral Irene , García Vázquez Miriam , Milagro-Beamonte Ana , Fernandez Ibañez Ana , Margolles Martins Mario , Giménez Duran Jaume , Sastre Palou Bartolomé , López Causapé Carla , Viloria Raymundo Luis Javier , Vega Alonso Tomás , Ordax Díez Ana , Lozano Alonso Jose Eugenio , Rojo Bello Silvia , Mendioroz Jacobo , Basile Luca , Martínez Mateo Ana Isabel , Ruiz de Porras Carlota , Moya Garcés Alba , Marcos Mª Ángeles , López Maside Aurora , Botella Quijal Francesc , Miralles Espi Maite , Andreu Salete Cristina , García Rodríguez María del Carmen , Linares Juan Antonio , García Comas Luis , Barranco Mª Isabel , Chirlaque María-Dolores , Moreno Docón Antonio , Ramos Marín Violeta , Castrillejo Daniel , Gómez Anés Atanasio , Larrauro Amparo , Pérez-Gimeno Gloria , Lozano Álvarez Marcos , Vega Lorena , Galindo Silvia , Puma Tania , Monge Susana , Pozo Francisco , Casas Inmaculada , Sandonis Virginia , Vázquez-Morón Sonia , Echeverría Aitziber , Trobajo-Sanmartín Camino , García Cenoz Manuel , Ezpeleta Guillermo , Ezpeleta Carmen , Navascués Ana , Krisztalovics Katalin , Mucsányiné Juhász Krisztina , Kristóf Katalin , Preuss Ute , Wedde Marianne , Biere Barbara , Reiche Janine , Oh Djin-Ye , McKenna Adele , Connell Jeff , Joyce Michael , Bagheri Mariam , Bos Sanne , van den Brink Sharon , Dijkstra Frederika , Eggink Dirk , van Gageldonk-Lafeber Rianne , Goderski Gabriel , Herrebrugh Chantal , Jenniskens Liz , Reukers Daphne , Sluimer John , Sprong Tara , Teirlinck Anne , Veldhijzen Nienke , van der Burgh Ruben , Kager Cathrien , Klinkhamer Mayra , Knottnerus Bart , Riethof Marloes , van den Broek Ruud , Wortel Safira , Machado Ausenda , Kislaya Irina , Aniceto Carlos , Gomes Licínia , Verdasca Nuno , Henriques Camila , Dias Daniela , Lança Miguel , Blanchon Thierry , Guerrisi Caroline , Renard Aubane , Launay Titouan , Masse Shirley , Chazelle Marie , Ferenčak Ivana , Kaić Bernard , Višekruna Vučina Vesna , Čusek Adamić Katica , Kosanović Ličina Mirjana Lana , Lakošeljac Danijela , Mihin Huskić Ivana , Nonković Diana , Carnahan Annasara , Hansson-Pihlainen Eva , Arvesen Elin , Nid Nora , Hansen Anna-Lena , Andersson Emmi , Dillner Lena , Jidovu Adrian , Timnea Olivia Carmen , Pascu Cătălina , Oprea Mihaela , Bistriceanu Iulia , Ivanciuc Alina , Mihai Maria Elena ,   VEBIS Primary Care Vaccine Effectiveness Group
Published: July 2024

ImportanceIn the context of emerging SARS-CoV-2 variants or lineages and new vaccines, it is key to accurately monitor COVID-19 vaccine effectiveness (CVE) to inform vaccination campaigns.ObjectiveTo estimate the effectiveness of COVID-19 vaccines administered in autumn and winter 2022 to 2023 against symptomatic SARS-CoV-2 infection (with all circulating viruses and XBB lineage in particular) among people aged 60 years or older in Europe, and to compare different CVE approaches across the exposed and reference groups used.Design, Setting, and ParticipantsThis case-control study obtained data from VEBIS (Vaccine Effectiveness, Burden and Impact Studies), a multicenter study that collects COVID-19 and influenza data from 11 European sites: Croatia; France; Germany; Hungary; Ireland; Portugal; the Netherlands; Romania; Spain, national; Spain, Navarre region; and Sweden. Participants were primary care patients aged 60 years or older with acute respiratory infection symptoms who were recruited at the 11 sites after the start of the COVID-19 vaccination campaign from September 2022 to August 2023. Cases and controls were defined as patients with positive and negative, respectively, reverse transcription–polymerase chain reaction (RT-PCR) test results.ExposuresThe exposure was COVID-19 vaccination. The exposure group consisted of patients who received a COVID-19 vaccine during the autumn and winter 2022 to 2023 vaccination campaign and 14 days or more before symptom onset. Reference group included patients who were not vaccinated during or in the 6 months before the 2022 to 2023 campaign (seasonal CVE), those who were never vaccinated (absolute CVE), and those who were vaccinated with at least the primary series 6 months or more before the campaign (relative CVE). For relative CVE of second boosters, patients receiving their second booster during the campaign were compared with those receiving 1 booster 6 months or more before the campaign.Main Outcomes and MeasuresThe outcome was RT-PCR–confirmed, medically attended, symptomatic SARS-CoV-2 infection. Four CVE estimates were generated: seasonal, absolute, relative, and relative of second boosters. CVE was estimated using logistic regression, adjusting for study site, symptom onset date, age, chronic condition, and sex.ResultsA total of 9308 primary care patients were included, with 1687 cases (1035 females; median [IQR] age, 71 [65-79] years) and 7621 controls (4619 females [61%]; median [IQR] age, 71 [65-78] years). Within 14 to 89 days after vaccination, seasonal CVE was 29% (95% CI, 14%-42%), absolute CVE was 39% (95% CI, 6%-60%), relative CVE was 31% (95% CI, 15% to 44%), and relative CVE of second boosters was 34% (95% CI, 18%-47%) against all SARS-CoV-2 variants. In the same interval, seasonal CVE was 44% (95% CI, −10% to 75%), absolute CVE was 52% (95% CI, −23% to 82%), relative CVE was 47% (95% CI, −8% to 77%), and relative CVE of second boosters was 46% (95% CI, −13% to 77%) during a period of high XBB circulation. Estimates decreased with time since vaccination, with no protection from 180 days after vaccination.Conclusions and RelevanceIn this case-control study among older Europeans, all CVE approaches suggested that COVID-19 vaccines administered in autumn and winter 2022 to 2023 offered at least 3 months of protection against symptomatic, medically attended, laboratory-confirmed SARS-CoV-2 infection. The effectiveness of new COVID-19 vaccines against emerging SARS-CoV-2 variants should be continually monitored using CVE seasonal approaches.