Systematic review of the effectiveness and safety of live attenuated influenza vaccine in children

doi:10.5246/jcps.2026.02.012

Abstract

Abstract:

Live attenuated influenza vaccine (LAIV) is a needle-free, intranasal vaccine widely used in pediatric populations due to its ease of administration and its ability to induce mucosal immunity. This systematic review evaluated the effectiveness and safety of LAIV in children by analyzing data from clinical trials and real-world studies. The findings demonstrated that LAIV elicited robust mucosal IgA responses, approximately tenfold higher, and strong systemic antibody responses, particularly against H1N1 and B strains, although its efficacy against H3N2 remained comparatively lower. Safety assessments showed that LAIV was generally well-tolerated, with mostly transient mild adverse events and rare occurrences of serious reactions. However, a slight increase in wheezing episodes was observed in children with asthma, indicating a need for caution in this subgroup. When compared to inactivated influenza vaccines (IIV), LAIV provided comparable protection while offering the additional benefit of reducing transmission in community settings. Challenges such as interference from pre-existing immunity and limited thermo-stability were noted, but advancements in next-generation LAIV formulations hold promise for addressing these limitations. Overall, LAIV continues to be a valuable tool for pediatric influenza prevention, especially for needle-averse populations, although strain-specific optimization and further safety improvements remain necessary.

Key words: LAIV, Children, Effectiveness, Safety, Systematic review

Supporting:

Cong Li, Yi Huang, Ruxing Yang, Sini Zou, Jianrong Wang, Zhen Li. Systematic review of the effectiveness and safety of live attenuated influenza vaccine in children[J]. Journal of Chinese Pharmaceutical Sciences, 2026, 35(2): 162-172.

Figures/Tables 5

Table 1. The comparisons between LAIV and IIV.

Table 2. The LAIV safety profile in children from 2014 to 2024.

Table 3. The effectiveness of LAIV in children.

Table 4. The total LAIV effectiveness in children from 2014 to 2024.

Table 5. The comparisons between DelNS1-2019-nCoV-RBD-OPT1 and LAIV.

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