The virus, often colloquially referred to as “stomach flu,” saw the percentage of positive tests double during the first week of January compared to last year. Positive test percentages for cases of norovirus in the United States are double what they were at the same period a year ago,

The latest wave of norovirus infections have more than doubled last season's peak, the CDC said. Almost 30% of norovirus tests taken the week of new year's were positive for the virus. Rates have reached or surpassed last season's peaks in all regions across the country.