Seasonal COVID-19 vaccination campaigns in Europe targeted older adults while SARS-CoV-2 circulation was declining after a period of high activity. A Research Letter in JAMA Network Open presents primary care data from France, Germany, Ireland, Italy and Spain on vaccine effectiveness during the autumn and winter 2025 to 2026 campaigns. The assessment focused on medically attended, symptomatic SARS-CoV-2 infection and compared vaccinated and unvaccinated patients using consultation data, laboratory testing and vaccination status. It offers a timely view of short-term protection during a campaign period with varying national age thresholds and changing virus activity.
Primary Care Data Across Five Countries
The European primary care network included patients with acute respiratory infection who attended a primary care physician after the start of the seasonal vaccination campaigns. Eligible patients belonged to the older target group for vaccination in their country. The minimum age threshold was not identical across participating countries, ranging from 60 to 70 years. Patients were swabbed either as a complete eligible group or through systematic sampling. Laboratory testing separated those with confirmed SARS-CoV-2 infection from those who tested negative.
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Vaccination status followed the timing of the seasonal campaign. A vaccinated patient had received a COVID-19 vaccine dose during the campaign and developed symptoms at least 14 days later. Patients counted as unvaccinated had not received a campaign dose, had not been vaccinated in the preceding 3 months or received vaccination on or after the day symptoms began. The analysis adjusted for study site, symptom timing, age and sex. Additional checks considered chronic conditions and the effect of removing influenza cases from the comparison group. Ethical and consent requirements differed across countries, with some settings treating the work as routine care or surveillance and others applying local approval and consent procedures.
Vaccination Uptake Was Lower Among Cases
The dataset included more than 2000 older adults, with a relatively small number testing positive for SARS-CoV-2. Median age was in the early 70s in both the positive and negative groups. Women made up a larger share of both groups, and chronic conditions were common among patients with available information. The five participating countries contributed different numbers of patients, reflecting national recruitment and the structure of the primary care network.
Vaccination during the autumn and winter campaign was less frequent among patients with confirmed SARS-CoV-2 infection than among those who tested negative. Only a small minority of positive cases had received vaccination during the campaign, while vaccination was more common among controls. The typical interval between vaccination and symptoms was just over a month in both groups. Where vaccine brand was known, almost all vaccinated patients had received Comirnaty. Among those with known valency, the vaccines were adapted to the SARS-CoV-2 LP.8.1 variant. Sequencing data were available for only a limited subset of positive samples by February 2026. Most sequenced samples belonged to the XFG lineage, with one sample belonging to NB.1.8.1.
Effectiveness Remained Moderate in the Short Term
The pooled estimate showed COVID-19 vaccine effectiveness of 59% against symptomatic, medically attended SARS-CoV-2 infection among older adults. Protection was measured after the first 14 days following vaccination, in line with the campaign timing used to classify vaccine exposure. Within the first 2 months after vaccination, effectiveness remained slightly above 50%. The estimate was higher during the earlier post-vaccination interval than during the later interval, although uncertainty was wider at the later point.
Sensitivity checks produced similar results, with only small changes in the estimates. Penalised regression, applied where data were sparse according to predefined criteria, also produced estimates close to the standard regression approach. Sparse data rules limited reporting where small counts could make estimates unstable. This mattered because SARS-CoV-2 circulation had declined after the campaigns began, leaving fewer positive cases for analysis than might occur during a higher-incidence period. The limited sample size requires caution when interpreting the exact level of protection and when considering the best timing for seasonal vaccination campaigns. Even so, the findings indicate meaningful short-term effectiveness among older adults who received vaccination during the 2025 to 2026 campaign period.
The European primary care data show that COVID-19 vaccination during the 2025 to 2026 autumn and winter campaigns provided moderate short-term protection against symptomatic SARS-CoV-2 infection requiring primary care attendance among older adults. The pattern remained broadly stable across sensitivity checks, despite a limited number of positive cases and reduced SARS-CoV-2 circulation. Low uptake among eligible older adults stands out because vaccination was associated with protection during the early months after the campaign. The findings support continued attention to campaign timing, uptake and monitoring in vulnerable older groups.
Source: JAMA Network Open
Image Credit: iStock
References:
Laniece Delaunay C, Mateo-Urdiales A, Pérez-Gimeno G et al. (2026) COVID-19 Vaccine Effectiveness Among Older Adults. JAMA Netw Open;9(6):e2619040.
