The number of negative pressure rooms has been boosted by nine at the King Edward VII Memorial Hospital as part of the effort to battle the spread of Covid-19.The Bermuda Hospitals Board said it had added four negative pressure rooms in the Emergency Department, two in operating theatres, two in post-anaesthesia care and one in the dialysis unit.The isolation rooms are in addition to the 28 converted on the Ace Barber Unit, which was announced last week.The acute-care wing opened in 2014 with two negative pressure rooms in each of the three units, and 15 in the Emergency Department.Patients with infectious conditions are often housed in negative pressure isolation rooms.The BHB said Black & McDonald, the manager of the acute-care wing, used the automated building management system to convert the rooms.