BACKGROUND: Many options are available for preventing people from getting infected by influenza virus, with vaccination being the most widely used.
METHODS: We assessed the evidence available in Cochrane systematic reviews. We found nine reviews, five of them addressing influenza vaccination, and four addressing medication.
RESULTS: Vaccination is effective in healthy adults and children, but the effect is modest in adults, and for young children few data are available. In patients with asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis, more evidence is needed to determine effectiveness. Vaccination does not result in exacerbation of asthma. Neuraminidase inhibitors may also have a place in limiting the spread of infection, at least in adults. Amantadine and rimantadine seem effective but have unfavourable adverse-effect profiles. The popularity of homoeopathic Oscillococcinum, especially in France, is not supported by current evidence.
CONCLUSION: In many areas, more clinical trials are needed, as the current evidence is inconclusive. Furthermore, several other measures that may be helpful in preventing influenza that have not been addressed in Cochrane reviews.