The 2002–2004 outbreak of SARS, caused by severe acute respiratory syndrome coronavirus (SARS-CoV or SARS-CoV-1), infected over 8,000 people from 30 countries and territories, and resulted in at least 774 deaths worldwide.
The outbreak was first identified in Foshan, Guangdong, China, in November 2002. The World Health Organization (WHO) was notified of the outbreak in February 2003, and issued a global alert in March 2003. Initially, the cause of the outbreak was unknown, and some media outlets reported that an influenza virus was a potential culprit. The major part of the outbreak lasted about 8 months, and the World Health Organization declared SARS contained on 5 July 2003. However, several SARS cases were reported until May 2004.
In late December 2019, SARS-CoV-2, a coronavirus in the same genus as the one that caused SARS, was discovered in Wuhan, Hubei, China. This strain causes COVID-19, which spread to other areas of Asia, and then worldwide in early 2020, marking the start of the COVID-19 pandemic.
Outbreak by country and territory
On 16 November 2002, an outbreak of severe acute respiratory syndrome (SARS) began in China's Guangdong province, bordering Hong Kong. The first case of infection was traced to Foshan. This first outbreak affected people in the food industry, such as farmers, market vendors, and chefs. The outbreak spread to healthcare workers after people sought medical treatment for the disease. The People's Republic of China notified the World Health Organization (WHO) about this outbreak on 11 February 2003, reporting 305 cases including 105 health-care workers and five deaths. Later, it reported that the outbreak in Guangdong had peaked in mid-February 2003. However, this appears to have been false because subsequently 806 cases of infection and 34 deaths were reported. Italian physician Carlo Urbani was the first to identify SARS as probably a new and dangerously contagious viral disease.
Early in the epidemic, the Chinese government discouraged its press from reporting on SARS, delayed reporting to WHO, and initially did not provide information to Chinese outside Guangdong province, where the disease is believed to have originated. Also, a WHO team that travelled to Beijing was not allowed to visit Guangdong province for several weeks. This resulted in international criticism, which seems to have led to a change in government policy in early April.
A fishmonger, named Zhou Zuofen, checked in to the Sun Yat-sen Memorial Hospital in Guangzhou on 31 January, where he infected 30 nurses and doctors. The virus soon spread to nearby hospitals.
In February 2003, Liu Jianlun became Hong Kong's SARS index patient. He and his wife had come to attend a wedding; Liu was on the staff at Sun Yat-Sen Memorial Hospital in Guangzhou and had treated SARS patients.
On 21 February, Liu and his wife checked into room 911 on the ninth floor of the Metropole Hotel. Despite feeling ill he and his family traveled around Hong Kong. By the morning of 22 February, he knew he was very ill and walked to the Accident and Emergency Department of Kwong Wah Hospital to seek treatment. He was treated by the triage nurse and doctor without protective measures even though a memorandum on surveillance of severe community-acquired pneumonia had been issued by the Hospital Authority of Hong Kong. After Liu's chest X-ray taken in Kwong Wah Hospital became available, staff became aware of the situation, wearing personal protective equipment and full isolation inside the ICU. He did not recover and died on 4 March.
Liu is believed to have been a SARS super-spreader: 23 other Metropole guests developed SARS, including seven from the ninth floor. Liu's brother-in-law, who sought treatment in late February, was hospitalized in Kwong Wah Hospital on 1 March and died on 19 March. It is estimated that around 80% of the Hong Kong cases were due to Liu.
The virus was carried to Hanoi, Vietnam, by Chinese-American Johnny Chen, a resident of Shanghai who had roomed across the hall from Liu at the Metropole. He was admitted to the French Hospital of Hanoi on 26 February, where he infected at least 38 members of the staff. Even though he was evacuated, he died on 13 March. Carlo Urbani, a World Health Organization (WHO) infectious disease specialist, was among the staff who examined Chen. Urbani observed that other hospital staff were already falling ill and realized that he was dealing with a new and dangerous disease. He himself became infected and died on 29 March.
On 23 February, an elderly woman named Kwan Sui-Chu who had also been a Metropole Hotel guest, returned to Toronto, Canada, from Hong Kong. She died at home on 5 March, after infecting her son Tse Chi Kwai, who subsequently spread the disease to Scarborough Grace Hospital and died on 13 March.
On 1 March, 26-year-old Esther Mok, another Metropole guest, was admitted to Tan Tock Seng Hospital after visiting Hong Kong, starting the outbreak in Singapore. Although she recovered, various family members did not.
The first cases of atypical pneumonia in Taiwan were identified in a Guangdong-based businessman and his wife on 14 March and confirmed on 17 March. He had returned to Taiwan via Hong Kong on 23 February and reported a fever two days later. His wife became ill after caring for him, and both were admitted to National Taiwan University Hospital. Taiwan's third case of the disease was identified in a Yilan hospital on 15 March. Like the first case, the third case appeared in someone who had traveled to Guangdong and transited through Hong Kong before arriving in Taiwan. Shortly after the third case was diagnosed, officials from the Centers for Disease Control and Prevention in the United States traveled to Taiwan to study the disease. The fourth case, in another traveler to Guangdong, was identified in Chiayi on 18 March, after he sought treatment at a hospital the previous day. By 22 March, six cases in Taiwan had matched the World Health Organization definition of probable.
On 4 March, a 27-year-old man, who had visited a guest on the Metropole's 9th floor 11 days earlier, was admitted to Hong Kong's Prince of Wales Hospital. At least 99 hospital workers (including 17 medical students) were infected while treating him.
On 11 March, Carlo Urbani travelled to Bangkok, Thailand, to attend a medical conference. He fell ill during the flight and told a friend waiting in Bangkok not to touch him, to call an ambulance and take him to a hospital. He was isolated in an intensive care unit. A similar outbreak of a mysterious respiratory infection was reported among Hong Kong healthcare workers.
On 12 March, WHO issued a global alert about a new infectious disease of unknown origin in both Vietnam and Hong Kong. On 15 March, WHO issued a heightened global health alert about a mysterious pneumonia with a case definition of SARS after cases in Singapore and Canada were also identified. The alert included a rare emergency travel advisory to international travelers, healthcare professionals, and health authorities. The Centers for Disease Control (CDC) issued a travel advisory stating that persons considering travel to the affected areas in Asia (Hong Kong, Singapore, Vietnam, and China) should not go.
On 17 March, an international network of 11 laboratories was established to determine the cause of SARS and develop potential treatments.