Future studies on household transmission "should attempt to measure the details of interaction between ill and initially non-ill household members," Dr. France noted, such as hand washing and covering coughs, to determine how these behaviors, in addition to minimizing time spent with ill household members, factor into preventing transmission.

In an accompanying editorial, Ruth Lynfield, MD, of the Minnesota Department of Health, agreed and observed that the findings "are useful in reinforcing public health recommendations for infection control within households of infected individuals." When early action is most important at the beginning of a pandemic, Dr. Lynfield wrote, implementation is best reinforced by "data that support simple interventions in the household that are important for infection prevention."

The study also found a protective effect associated with preventive antiviral treatment, or prophylaxis. But the authors and the accompanying editorial highlight reports of the development of antiviral resistance and the need to reserve these drugs for influenza patients most at risk for developing complications, in line with recommendations from the Centers for Disease Control and Prevention (CDC).

Fast Facts

A household discussion about influenza prevention and transmission reduced the risk of family members passing on the virus to each other by 40 percent.

Transmission of the virus was rapid, with half of secondary influenza cases (in which one family member infected another) occurring within three days and almost 90 percent within one week.

To help prevent the spread of influenza, cover your nose and mouth when you cough or sneeze. Wash your hands often with soap and water.

Source: Infectious Diseases Society of America