Facemasks and Hand Hygiene to Prevent Influenza Transmission in Households. A Cluster Randomized Trial

The study was carried to investigate whether hand hygiene and use of facemasks prevents household transmission of influenza in households in Hong Kong. Sixty (8%) contacts in the 259 households had RT-PCR–confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant. In 154 households in which interventions were implemented within 36 hours of symptom onset in the index patient, transmission of RT-PCR–confirmed infection seemed reduced, an effect attributable to fewer infections among participants using facemasks plus hand hygiene (adjusted odds ratio, 0.33 [95% CI, 0.13 to 0.87]). Adherence to interventions varied. Ann Intern Med. 2009 Oct 6;151(7):437-46. Epub 2009 Aug 3.