Spread of viral infection to family members from influenza patients treated with a neuraminidase inhibitor.

We compared the incidence rates of household secondary infection among influenza patients prescribed laninamivir, oseltamivir, or zanamivir (neuraminidase inhibitors), based on health-insurance claims data owned by Japan Medical Data Center (JMDC) which was consisting of medical information on patients who were prescribed an anti-influenza drug and their family members between October 2010 and July 2011. The date when an index case patient was prescribed laninamivir, oseltamivir or zanamivir for the first time was defined as "Day 1". If other members in the same family were prescribed laninamivir, oseltamivir, zanamivir, or peramivir during Days 3-8, we assumed any household secondary infection had occurred. The incidence rate was 11.0%, 14.3%, and 11.6% in index case patients prescribed laninamivir, oseltamivir, and zanamivir, respectively. The results of the logistic regression analysis revealed a significant difference between laninamivir and oseltamivir, while no significant difference was observed between laninamivir and zanamivir.