The investigators studied households with an influenza positive index case. Study groups were wearing a facemask and practicing intensified hand hygiene (MH group), wearing facemasks only (M group) and none of the two (control group). Main outcome measure was laboratory confirmed influenza infection in a household contact.
When the hand washing and masks were introduced early in households, there was a significant reduction in the odds of transmission in the household (adjusted odds ratio 0.16, 95% CI, 0.03-0.92).
In the event of high influenza activity, promotion of hand hygiene and household mask use may be of benefit, especially when begun within 36 hours of symptom onset on the index (first) household case.
