- The Washington Times - Thursday, May 1, 2003

As scientists around the world work to find vaccines and diagnostic tests for SARS, some worry that the virus could mutate, making their job even more difficult.
"This has been very much on the mind of the virologists and those of us in public health," said Dr. William Schaffner, chairman of the department of preventive medicine and a professor of infectious diseases at the Vanderbilt Medical School in Nashville, Tenn. "If it did that, it would make the challenge of developing a vaccine very, very much greater."
"Time will tell, and it's one of the unanswered questions," said Dr. James M. Hughes, director of Infectious Disease at the Centers for Disease Control and Prevention (CDC). "What you need to do is monitor the virus over a period of time and see what happens."
Dr. Hughes said the HIV virus changes readily and "that is one of the reasons people have not been able to develop an effective vaccine."
Doctors are working to develop a vaccine for the pneumonialike illness known as severe acute respiratory syndrome. They are also trying to develop reliable tests to diagnose it and treatments to fight it.
Dr. Julie L. Gerberding, director of the CDC, talked Tuesday about efforts to develop a reliable diagnostic test, and noted SARS is a form of the coronavirus, which can change as it replicates itself.
"It would not be surprising for this to occur," she told a Senate panel.
Different types of the coronavirus have traditionally shown up in animals. They also have manifested in humans, but just result in common colds, Dr. Schaffner said. SARS, however, is a new form of coronavirus, so scientists do not know if it is going to evolve rapidly or remain stable.
But Dr. Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases, said this is not something he is extremely worried about.
He said the coronavirus has "quite a capability" of mutating because it is an RNA-based virus, and those do not have any "proofreading mechanism" to correct mistakes that happen as they replicate. But he said these changes typically do not make the virus any more or less virulent, just a little different.
"Does that mean it can't mutate to the point of being very different? No," he said. "[But] on face value, the concept of mutating doesn't inherently make me extremely concerned at this time, because coronaviruses tend to mutate."
Dr. Fauci also said vaccine development probably won't be impacted by small changes in the virus, as scientists aim vaccines against the parts of a virus that don't change.
If the SARS virus was to change notably, however, not only would vaccine development be more challenging, but the diagnostic tests being developed at the CDC might be ineffective as well, Dr. Schaffner said.
"You can make a test that can diagnose SARS 1, but can't diagnose SARS 2 or 3," Dr. Schaffner said.
But Dr. Fauci said it is "extremely unlikely that its going to mutate to the point that you wouldn't recognize it at all in your diagnostic" test.
Analysts say SARS could change in either a positive or negative direction meaning it could become more or less powerful.
As scientists continued their research, the situation in China worsened yesterday with an additional 166 probable SARS cases and 11 deaths, bringing the cumulative total to 3,460 cases and 159 deaths, according to the World Health Organization.
The SARS virus has now claimed 372 lives around the globe and infected 5,663 persons from 26 countries, the WHO reported yesterday.
The death rate from SARS is about 6 percent and rising, a WHO official said yesterday.
Meanwhile, Canada began a broad campaign to attract visitors yesterday after the WHO lifted its travel advisory against Toronto, saying the SARS situation has improved there.
An alert on the Drudge Report Web site yesterday said some people in Asia may have been reinfected with SARS, or relapsed. But Dr. Fauci checked with the CDC midday yesterday about this, and they could not confirm it. He said he has not heard it from any official authorities.

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