Eight wards in Midland hospitals remained closed last night as the winter vomiting bug continued to spread across the region.
Closures at Hereford County Hospital, University Hospital North Staffordshire and George Eliot Hospital in Nuneaton, Warwickshire, mean visitors are banned or restricted until further notice.
There were also 30 patients at four other Midland hospitals still suffering symptoms of vomiting and diarrhoea yesterday.
Heartlands Hospital in Bordesley Green, Birmingham, had 21 patients on isolation wards with the bug; Good Hope Hospital, in Sutton Coldfield, four, and Solihull Hospital had three cases of suspected norovirus yesterday.
Royal Wolverhampton Hospitals, which runs the city's New Cross Hospital, reported two cases of norovirus yesterday.
Lisa Dunn, hospital director at Heart of England Foundation NHS Trust - which runs Heartlands, Good Hope and Solihull - urged patients' friends and relatives to stay away if they develop similar symptoms.
She added: "You can still infect others even if you have stopped all symptoms and thus you should not visit for at least 48 hours after all symptoms have stopped. This is to protect patients, visitors and staff."
Hereford Hospitals NHS Trust, where four wards are closed to admissions, has banned visitors from all wards until further notice to minimise cross infection between patients and the community.
John Howden, trust director of human resources, said: "It is essential to take action wherever possible to stop the spread of the virus amongst patients and in the community.
"Special visiting arrangements are however in place for families of terminally ill patients, expectant parents and parents/guardians of children in the hospital."
Walsall Hospitals NHS Trust bosses confirmed three wards had been closed over the weekend and visitors were still banned.
Brigid Stacey, trust chief operating officer, said: "We continue in so far as we can to take necessary precautions in an attempt to prevent the spread of this virus.
"In view of the national scale of this out-break, we have taken the extra precaution of suspending visiting to the affected wards until further notice and would urge visitors not to come to the hospital if they have been unwell themselves, or indeed if they have been in contact with anyone who has been unwell, in the past 48 hours."
Previously wards at City Hospital, in Winson Green, Birmingham, and Sandwell General, in West Bromwich, had been forced to close wards but a spokesman said: "We seem to be over the worst of it and no wards are closed now."