This winter's wave of norovirus infections has reached levels that are now more than double last season's peak, the CDC says. Nearly 28% of norovirus tests run over the week of the New Year's holiday came back positive for the highly contagious virus. That is more than double the 13.52% of tests coming back positive reached during the peak of last season's wave in March, according to data from public health laboratories around the country tallied by the CDC.
