Oral Haemophilus influenzae vaccination v placebo for recurrent bronchitis*

Weighted event rates
OutcomesFollow upVaccinePlacebo RRR (95% CI)NNT (CI)
Antibiotic use6 months32%59%46% (13 to 66)4 (3 to 12)
Weighted mean decrease (CI)
*Fixed-effects model used for all outcomes. Abbreviations defined in glossary; NNT and CI calculated from data in article.
Bronchitis episodes3 months6.69 (6.42 to 6.96)
6 months4.47 (4.30 to 4.64)