The vaccines included in the study were live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV). Interim vaccine effectiveness estimates from identified studies were pooled using random-effects meta-analysis, and estimates were provided overall and by influenza subtype. Continuous analyses were conducted until May 2025 to encompass the 2024-2025 season.
Five studies were identified (totalling 10 European countries and the USA) that provided 34 interim estimates of vaccine effectiveness (11 for LAIV and 23 for IIV). Ms Giulia Di Lucchio (AstraZeneca, Italy) presented the results [1]. Overall, interim vaccine effectiveness was estimated at 55% (95% CI 47-62) for LAIV and 57% (95% CI 42-68) for IIV. Among serotypes, vaccine effectiveness was estimated at 50% (95% CI 34–62) and 55% (95% CI 34–69) for A/H1N1, and 76% (95% CI 55–87) versus 69% (95% CI 27–87) for influenza B. For A/H3N2, data were less precise, with estimates of 44% (95 %CI -529 to 95) and 37% (95% CI 17–53) vaccine effectiveness, respectively (see Figure). End-of-season UK data were available for LAIV and showed similar overall vaccine effectiveness.
Figure. Individual estimates of 2024/25 interim VE in children, by vaccine type and setting [1]
†Any setting. ‡Outlier due to small numbers contributing to the analysis. VE, vaccine effectiveness.
“This analysis provides an early assessment of vaccine effectiveness in the 2024–2025 influenza season, a season largely driven by influenza A/H1N1,” said Ms Di Lucchio. “We saw moderate protection against influenza, 55-60%, which was similar and comparable for the two vaccines. Point estimates suggested higher effectiveness for influenza B and lower effectiveness for A/H3N2. Finally, we saw that end-of-season estimates from the UK were broadly similar to the pooled interim vaccine effectiveness.”
- Enxing J, et al. Effectiveness of the live attenuated (LAIV) and inactivated (IIV) influenza vaccines in children: a meta-analysis of interim data (based on cases through February 2025) from the 2024/25 influenza season. 6th ESCMID Vaccines, 10–13 September 2025, Lisbon, Portugal.
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Table of Contents: ESCMID Vaccines 2025
Featured articles
Real-world data confirm PCV20 effectiveness against pneumococcal disease in adults aged ≥65 years
Pneumococcal Vaccination
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V116 shows promise for adults at risk of pneumococcal disease
Real-world data confirm PCV20 effectiveness against pneumococcal disease in adults aged ≥65 years
The V116 pneumococcal vaccine is a new option in children at risk for pneumococcal disease
Influenza and COVID-19 Vaccination
Omicron XBB.1.5 vaccination provides effective, but rapidly waning protection in immunocompromised individuals
Intranasal COVID-19 vaccine shows promising results in preclinical mouse models
Influenza vaccine in children shows moderate, broad protection during the 2024-2025 season
Lower age is linked to reduced uptake of influenza and COVID-19 vaccination
RSV vaccination and Immunisation
Combination respiratory vaccines show promise but face key challenges
Adjuvanted RSVPreF3 demonstrates high real-world effectiveness in the USA
RSV immunisation: Maternal versus direct infant immunisation
European pregnant women show openness to maternal RSV vaccination
Infants immunised with nirsevimab have a lower risk of respiratory-related recurrent hospitalisation
Adjuvanted RSVPreF3 can be co-administered with a COVID-19 mRNA vaccine in adults aged ≥50 years
Other Childhood and Routine Vaccinations
Pertussis vaccination: Could an intranasal vaccine help curb the rising cases of whooping cough?
Does the 2+1 vaccination schedule for Haemophilus influenzae type b increase case numbers?
Wastewater poliovirus detections in Europe may reflect seasonal infection patterns rather than consistent importation
Emerging and Future Vaccines
Where do we stand with vaccination for haemolytic streptococci?
The future looks promising for tuberculosis vaccination
Where do alternative vaccine administration routes fit in the clinical landscape?
Malaria immunisation beyond subunit vaccines: Current progress
SARI Definitions and Vaccine Effectiveness
Case definition discrepancies influence VE outcomes
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