The World Health Organization (WHO) is advising travelers to avoid both Hong Kong and China's Guangdong province because of the severe acute respiratory syndrome (SARS) outbreaks there. The WHO's infectious diseases chief, Dr. David Heymann, noted that "this is the first time we've recommended that people avoid a certain area because there's no vaccine and no drug." SARS has killed at least 75 people, and more than 1,800--the majority in Hong Kong and China--have become ill. WHO officials are worried about the way SARS is spreading in Hong Kong, since not all the cases seem to have stemmed from close contact with an infected person. Airlines say that passenger levels have dropped on flights to the affected areas. WHO spokesman Chris Powell says that the Chinese government has invited an investigative team to Guangdong, an invitation that has been confirmed by Qi Qingdong, the head of the Chinese Ministry of Health's Division of International Cooperation.