Surgical masks were as effective as respirators in protecting health care workers against the H1N1 flu at a hospital in Singapore, according to a study in the April 1 issue of Clinical Infectious Diseases. Health care workers at Tan Tock Seng Hospital in Singapore wore N95 respirators in the emergency room and an H1N1 isolation area from June 19 to July 21, then surgical masks in the same areas from July 22 to Aug. 31. The incidence of H1N1 among workers remained low during both periods.