Efficacy and safety of influenza vaccines in children

This Cochrane review evaluates the effectiveness and safety of influenza vaccines in healthy children, encompassing 41 randomized controlled trials (RCTs) with over 200,000 participants. The review assesses both live attenuated and inactivated influenza vaccines, comparing them to placebos or no intervention.
The findings reveal that live attenuated influenza vaccines (LAIV) likely reduce the risk of influenza from 18% to 4% in children aged 3 to 16 years (moderate-certainty evidence), and they may reduce influenza-like illness (ILI) from 17% to 12% (low-certainty evidence). The number needed to vaccinate (NNV) to prevent one case of influenza is 7, and to prevent one case of ILI is 20. However, data on the impact of LAIV on school absenteeism and parental work absence remain insufficient. Inactivated influenza vaccines (IIV) reduce the risk of influenza from 30% to 11% in children aged 2 to 16 years and probably reduce ILI from 28% to 20%. The NNV for IIV to prevent one case of influenza is 5, and to prevent one case of ILI is 12. The risk of otitis media appears similar between vaccinated and unvaccinated children, although the evidence is of moderate certainty. Adverse event reporting varied significantly across studies, with some evidence of fever following vaccination but insufficient data on nausea and hospitalization. The review concludes that both LAIV and IIV can effectively reduce the incidence of influenza in healthy children, though the variability in results suggests further research is needed to assess their impact across different settings and seasons.