|
March-April 2007
|
The SARS Scare
|
 |
Reuters/Corbis |
Chinese doctors and nurses wear protective gear as they tend to a SARS patient in a Beijing hospital. |
Ironically, in this age of high-tech medicine, the virus was eventually brought under control by public-health measures typically associated with the nineteenth century—isolation of SARS patients themselves and quarantine of all their known and suspected contacts—rather than a vaccine. But it was tools of the modern era, including high-speed communications and sophisticated computer modeling, that allowed epidemiologists at Harvard and in the United Kingdom to initially determine that such an approach could work at all. The relatively slow spread of the SARS virus as compared to flu made it more a warning to humanity than the full-fledged pandemic that was feared: had SARS been more infectious or incubated more rapidly, such old-fashioned containment methods would have failed.
Sidebar:
Bird Flu
The threat, of course, is that our luck might not hold next time. That makes it vital to learn from the scientific, public-health, and political responses to what did happen. SARS is the story of a global network of medical workers, epidemiologists, virologists, and other scientists who responded to a sudden threat with record speed, aided by new technologies that allowed them to identify the virus, decipher its genetic code, and publish it on the Internet. Harvard microbiologists and molecular geneticists then played a central role, using the published genome to build the virus’s entry mechanism, a spike-like protein, from scratch, and used that, in turn, to identify the receptor the virus uses to penetrate human cells. This breakthrough laid the groundwork for short-term therapeutic interventions and targeted vaccine development.
After a second, small outbreak in 2004, scientists were able to pinpoint the genetic change in the viral genome that had allowed SARS to infect humans, and to validate initial suspicions about what animal had last incubated the disease before it jumped to humans. Harvard School of Public Health (HSPH) professionals briefed domestic political leaders during the initial outbreak, and China, criticized at first for being slow to respond, invited HSPH dean Barry Bloom to meet the minister of health to consider how the school “might help them improve their response to emerging public-health challenges.” (In August 2006, the first group of rising mid-level officials in China’s central and provincial ministries of health completed a three-week training program at the school, led by Yuanli Liu, an assistant professor of international health.)
 |
World Health Organization Regional Office for the Western Pacific 2005
|
This diagram detailing SARS transmission in Singapore shows the important role of “super-spreaders” in transmitting the disease. Five people caused more than half of the 205 cases there. |
SARS was declared eradicated by the World Health Organization (WHO) in 2005. Whether or not it returns to afflict humans, the disease has taught us much about our lack of readiness for the next emergent infection; raised many questions about the conditions that lead to surprisingly frequent outbreaks such as SARS, Ebola, bird flu, and Nipah virus; and suggested how public-health and molecular medicine best work together in the prevention and control of new diseases.
Allan Detsky, M.D. ’78, chief of medicine at Mount Sinai Hospital in Toronto, worked at the epicenter of the outbreak in North America. “I was in Vancouver attending my niece’s bat mitzvah,” he recalls, “and there was a story on the news about a case of this weird disease in Toronto. This was around March 15, 2003.” Detsky had read reports of a new pneumonia-like illness that was spreading rapidly in Hong Kong. Now it appeared it might have reached Canada. “Then they showed a picture of my hospital,” he says, and he cursed.
“As it turned out, the SARS case was not in my hospital after all,” Detsky continues. Two of his infection-control specialists were consulting to Scarborough Grace Hospital, about 10 miles away, where the patient was being treated. But Detsky was right to be worried. SARS—a zoonosis, or disease that spreads through animals—had first infected a man in Guangdong Province, in China, the previous November. A second, epidemiologically unrelated case cropped up there in mid December. By the end of January, numerous instances of the disease had been reported, with a cluster among people who worked in the flourishing live-animal markets of the area, which provide exotic meats for a growing middle-class clientele. Then, on January 30, the first known super-spreading event took place, when a 44-year-old seafood seller hospitalized in Guangzhou passed the virus to 19 relatives and 50 or more hospital staff members. Three weeks later, a doctor from that hospital—he had been suffering flu-like symptoms for a week—traveled to Hong Kong to attend a wedding. During a one-night stay on the ninth floor of the Metropole Hotel, he infected 17 people. None of the other Metropole cases had had any known contact with him, suggesting that the live virus had become airborne. From the cosmopolitan nexus of the hotel, SARS began to spread internationally to Singapore, Vietnam, the Philippines, Australia, and Canada.
The first Canadian case went undetected: a 78-year-old woman who had stayed in the Metropole on February 21, nearly two weeks before, died at her home back in Canada. The official cause of death was a heart attack. But that proved to be a complication of SARS, which she had unwittingly passed on to four family members. Two days later, on March 7, the woman’s son appeared in the emergency room of a hospital in Scarborough with a cough, fever, and difficulty breathing. Though quickly isolated when a doctor suspected tuberculosis, the man had already passed the virus to three other people while waiting 18 to 20 hours to be seen. A week later, one of them returned to the hospital after suffering a heart attack. Although that victim’s contact with the woman’s son (who died the very same day) was already known, the patient’s symptoms were not thought to be pneumonia-like, and he was transferred to another hospital. There he infected more than 50 people.
“SARS has about a 10-day incubation,” says Detsky, “so for the first 10 days we lowered our guard and thought maybe this was overblown, maybe the problem was that in Hong Kong they don’t really know how to do respiratory care. Of course, that is bullshit. They are as advanced in Hong Kong as they are anywhere.”
1 | 2 | 3 | 4 | continued >
