Saunders-Hastings, P., Crispo, J., Sikora, L., et al. (2017). Effectiveness of Personal Protective Measures in Reducing Pandemic Influenza Transmission: A Systematic Review and Meta-Analysis. Epidemics.
This meta-analysis examined the effectiveness of hand hygiene, respiratory etiquette, and use of facemasks in reducing the risk of pandemic influenza transmission. The authors did not find data on the effectiveness of respiratory etiquette, but found that hand hygiene was statistically significant and wearing a face mask was suggestive of preventing infection.