Arthur Van Langerberg, a virologist working at Canossa Hospital in Hong Kong, told La Repubblica that developing a vaccine to battle sudden acute respiratory syndrome (SARS) will not be easy, because of the virus' ability to mutate quickly. Even if a vaccine is developed in the next six months, says Van Langerberg, the virus will probably have mutated in that time and the vaccine will therefore have limited benefit. The virologist said that SARS could spread across Europe in the coming winter, as that is the time when most people develop colds, which are related to the illness.