Norovirus outbreak management: how much cohorting is necessary?

Summary For the control of norovirus outbreaks, it is widely recommended that exposed but asymptomatic patients should be cohorted separately from unexposed patients and from symptomatic patients. The frequency of subsequent symptomatic norovirus infection in contact patients has not been investigated systematically. We retrospectively investigated the development of typical norovirus symptoms in contact patients during seven norovirus outbreaks affecting 57 patients between November 2014 and May 2015. Only one of 14 contact patients developed typical norovirus symptoms, calling into question current recommendations to isolate contact patients.