Paramedics performing life support remove an injured man's necktie as a first step to ensure it does not block his airway. Neckties might also be a health risk for persons other than the wearer. They are believed to be vectors in disease transmission in hospitals. Notwithstanding such fears, many doctors and dentists wear neckties for a professional image. Hospitals take seriously the cross-infection of patients by doctors wearing infected neckties, because neckties are less frequently cleaned than most other clothes. On September 17, 2007, British hospitals published rules banning neckties. In such a context, some instead prefer to use bow ties due to their short length and relative lack of hindrance.