Indirect Influenza Vaccine Effectiveness Under Randomized Conditions: A Systematic Review and Meta-Analysis.
Andrew C Gilmore, Yuanyuan Liang, Ian M Galbreath et al.
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In 30 seconds
This systematic review and meta-analysis evaluated the indirect vaccine effectiveness (IVE) of influenza vaccines in non-institutional settings, analyzing data from 12 randomized controlled trials. The pooled direct vaccine effectiveness (DVE) was 44.1%, while the pooled IVE was significantly lower at 13.7%, with most trials showing no statistically significant indirect effects.
Key findings
- Pooled direct vaccine effectiveness (DVE) was 44.1% (95% CI: 29.6%, 55.6%).
- Pooled indirect vaccine effectiveness (IVE) was 13.7% (95% CI: 1.5%, 24.5%).
- Nine of the twelve trials had confidence intervals that included zero for IVE.
- The review found no evidence of publication bias.
Why it matters
Understanding the effectiveness of influenza vaccines, particularly indirect effects, is crucial for public health strategies. The findings suggest that individual vaccination remains the most effective method for preventing influenza, rather than relying on community-level immunity.