Comparative Effectiveness of Live Attenuated Influenza Vaccine (LAIV) and Inactivated Influenza Vaccine (IIV) in Children

Strategic Insights -

A recent study published in Vaccine: X has evaluated the comparative effectiveness of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) in children across 13 European countries and the US during the 2019-2023 influenza seasons. The research, conducted by AstraZeneca, aimed to assess the vaccine effectiveness (VE) of LAIV4 and IIV4 in children. The findings suggest that annual vaccination with LAIV4 or IIV4 remains the best way to protect children against influenza infection.

Key Takeaways:

  • The study evaluated the VE of LAIV4 and IIV4 in children across 13 European countries and the US during the 2019-2023 influenza seasons.
  • The meta-analysis included 34-1679 children from included studies during the 2019/20-2022/23 seasons.
  • LAIV4 VE estimates against influenza infection (all strains) were 61.9% (95% CI: 53.0-69.1) and for IIV4 were 45.7% (33.2-55.8).
  • Overall VE (95% CI) for individual strains for the 2022/23 season for LAIV4 were 75.7% (52.0-87.7) and for IIV4 were 58.5% (38.2-72.1).
  • The study concluded that annual vaccination with LAIV4 or IIV4 remains the best way to protect children against influenza infection.
  • The research was conducted by AstraZeneca, with additional authors including George Kassianos, Oliver Dibben, and Georges El Azzi.

Statistics:

  • The study included 34-1679 children from included studies during the 2019/20-2022/23 seasons.
  • LAIV4 VE estimates against influenza infection (all strains) were 61.9% (95% CI: 53.0-69.1).
  • IIV4 VE estimates against influenza infection (all strains) were 45.7% (33.2-55.8).
  • Overall VE (95% CI) for individual strains for the 2022/23 season for LAIV4 were 75.7% (52.0-87.7).
  • The 2022/23 season's overall VE for IIV4 were 58.5% (38.2-72.1).

Sources:

  • Comparative effectiveness of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) in children over multiple influenza seasons (2019-2023). Vaccine: X, 2025,25():100666.
  • https://doi-org.sdpl.idm.oclc.org/10.1016/j.jvacx.2025.100666