A Randomised Controlled Trial on the Effect of Post-exposure Oseltamivir Prophylaxis on Influenza Transmission in Nursing Homes

The incidence of severe morbidity and mortality following an influenza infection during the annual influenza epidemics is highest among the elderly population and 90% of influenzaassociated mortality occurs in this group. Vaccination is considered the best preventive intervention available but offers only partial protection. The protective effect decreases with advancing age and existing co-morbidity. Therefore, in spite of high compliance with vaccination, the risk of influenza-related complications among nursing-home residents, is particularly high, and consequently also the associated disease and economic burden. There is debate on the potential health benefit of the antiviral activity of oseltamivir as an effective supplementary intervention to prevent or contain influenza outbreaks in nursing homes. Although effectiveness of post-exposure prophylaxis (PEP) with oseltamivir on preventing transmission has been demonstrated in trials among healthy (mainly unvaccinated) adults and children, effectiveness has not yet been assessed among vulnerable vaccinated highrisk groups, such as the elderly population in nursing homes. If proven (cost)effective, oseltamivir could have considerable benefits in this setting, although constraints relating to implementation need to be addressed as well.