Winter vomiting cases have forced the closure of 19 hospital wards in Birmingham and the West Midlands.
Health chiefs have recorded 93 confirmed or suspected Norovirus outbreaks this month, compared to 24 in the same period last year.
Figures also show the 19 hospital wards have closed in Birmingham, the Black Country, Staffordshire, West Mercia, and Arden in Warwickshire, blocking a total of 105 beds.
The closures include Ward 22 at Heartlands Hospital, Bordesley Green, whilst Ward 11 at Good Hope Hospital, Sutton Coldfield is also shut to visitors.
Ward D17 at City Hospital, Winson Green, has also been closed to new admissions, after six patients showed symptoms of the bug. Visiting is at the discretion of the ward manager.
A spokesman for the Health Protection Agency (HPA) said: “Norovirus spreads easily, so it is important to be aware of the symptoms and what to do to prevent it spreading.
“Good hygiene is vital in preventing yourself or others from becoming infected.
“This includes thorough hand-washing, especially after using the toilet and any contaminated surface should be thoroughly disinfected after an episode of illness.
“Preparing food should also be avoided until three days after symptoms have disappeared.”