The Truth About SARS
It's deadly, infectious and not going away. What public-health officials have learned about the new virus–and how scared we should be

So far, the U.S. has been lucky. it has been nearly six months since the SARS outbreak emerged and more than six weeks since the illness spread from its birthplace in southern China to put the world on alert. Yet with more than 4,800 cases in at least 26 countries to date, a disease that has rocked Asian markets, ruined the tourist trade of an entire region, nearly bankrupted airlines and spread panic through some of the world's largest countries has largely passed the U.S. by.

Americans should not count on their sophisticated health-care system to protect them. China may be relatively backward, but Hong Kong, with a modern medical system, has experienced about as many deaths as have been reported in the rest of China put together. And only a few hours' drive from Buffalo, N.Y., just across the Canadian border, Toronto thought it had done just about everything possible to contain its outbreak–yet it keeps losing ground.

With fewer than 300 known SARS deaths so far, the worldwide toll is tiny compared with, say, the 3 million people who died of aids last year. But if SARS continues to spread, its numbers could skyrocket. Its overall death rate of about 6% is far lower than that of aids, Ebola or malaria, but if enough people catch the illness, even a low rate could cause a catastrophe. The Spanish flu epidemic of 1918—19 had a death rate of less than 3%, but so many people became infected that it killed more than 20 million people in just 18 months.

The financial toll, meanwhile, is already catastrophic. All told, says the World Health Organization (WHO), the global cost of SARS is approaching $30 billion. Nobody can forecast how much worse it could get. The more victims there are, the greater the chance that SARS will spread–and there may be a lot more cases in China than anyone realizes.

CURBING THE SPREAD

Despite intensive research in labs all over the world, scientists still have more questions than answers about SARS and the coronavirus that causes it. One mystery is where the disease came from. Coronaviruses have long been known to veterinary medicine because they routinely infect livestock, ducks and other domestic animals. In humans they had never caused anything worse than a cold, but this strain is clearly different.

Meanwhile, top virologists in the U.S., Canada, Hong Kong, Germany and several other nations have linked up to create a sort of virtual research lab. Their goal: to understand the virus itself. They identified the SARS virus several weeks ago, and now they are trying to come up with diagnostic tests. The virtual lab and independent biotech companies have already come up with several tests, but they are not yet reliable enough to be widely deployed.

Yet another open question is precisely how the disease spreads. Doctors first concluded that the agent responsible for SARS is transmitted by droplets expelled by coughs or sneezes. After the burst of cases in Hong Kong's Amoy Gardens complex and the particularly aggressive spread of SARS in Toronto among health-care workers, however, scientists now speculate that there may be other mechanisms as well. In Amoy Gardens, for example, transmission may have occurred via contaminated fecal matter leaking from a broken sewage pipe. That would explain the lack of direct contact, as well as the fact that all these cases, unlike those in mainland China and Toronto, are characterized by severe diarrhea.

RAPID MUTATION

It may also be that the microbe has mutated into several subtly different strains producing different symptoms. This might explain some of the perplexing transmission patterns seen on planes: people sitting next to SARS victims did not always get infected, while those across the aisle sometimes did. Perhaps the latter had used a lavatory immediately after an infected passenger.

Another factor scientists do not understand is the superspreader, a person who appears to pass the disease on with extraordinary efficiency. Part of the explanation may be in the individual's genetics. "We don't know what those genetic factors are yet," says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), "but they're not necessarily related to how sick the person is." Some experts suspect that superspreaders might have a more virulent strain of coronavirus or be co-infected with other microbes. Having multiple infections may, these scientists speculate, increase one's chance of passing on the disease.

The risk of death from SARS, meanwhile, may have less to do with a particular strain of the virus and more to do with the body's reaction to it. "The immunological and inflammatory response of the body," says Fauci, "could be contributing significantly to the damage in the lungs." But nailing that down, along with questions of whether survivors become immune to further infection and whether the disease is permanently with us, like aids, will take more research.

So will the search for a vaccine. The biotech company GenVec announced plans last week to collaborate with NIAID on a strategy to develop a vaccine. And the U.S. Army Medical Research Institute for Infectious Disease is screening thousands of compounds to see if any might slow or stop the disease.

WILL IT BREAK OUT HERE?

While the U.S. is better equipped than most countries to detect and contain epidemics, it's pure luck that it has not been hit harder. The more time that passes, the better the U.S. can learn from the experience of other countries. But as long as there are even small pockets of infection lingering anywhere in the world, an outbreak is always a threat. In a world as interconnected as ours, it may just be a matter of time before SARS strikes in the U.S. the way it has elsewhere. "It's too soon to count our chickens," says Fauci. "This is an evolving epidemic, and we need to take it very seriously."

—from TIME, May 5, 2003

Questions

1. What financial impact has the SARS outbreak had to date?

2. According to the article, why hasn't the U.S. been hit harder by SARS?