Researchers in the United States have begun developing a vaccine for severe acute respiratory syndrome, the mysterious flu-like illness that has killed 84 people and infected 2,300 people worldwide.
The Pharmaceutical Manufacturers Association of America held a teleconference on Thursday with senior representatives from the pharmaceutical industry, the Centers for Disease Control and Prevention, the FDA, the National Institutes of Health and the Department of Defense to talk about vaccine development for SARS.
NIH researchers, assuming that SARS is caused by a form of the coronavirus (the cause of the common cold), have already begun work to develop a vaccine. Officials at the CDC say they're 90 percent sure that coronavirus is the culprit.
The NIH asked for other researchers to build upon the work they've already started. But if they're wrong about the cause of SARS, the vaccine search would have to begin again from scratch.
"Until we start getting positive blood results back from the CDC, we're not going to know what the (victims) are ... infected with," said Dr. Jon Rosenberg, a California state public health official and infectious disease expert.
One group might have a head start. Researchers at St. Jude Children's Research Hospital in Memphis, Tennessee, have designed a way to develop vaccines that could lead to a SARS vaccine, assuming they can identify the origin of the virus.
Known as reverse genetics, the method offers a more specific approach to developing a vaccine than current methods employ. Researchers hope it will yield results more quickly.
The standard method involves injecting a chicken egg with eight virus genes (six generic virus genes and two from the virus in question). Inside the egg, the genes combine to form a single version of the virus that contains all eight genes and can then be used as a vaccine. However, the process of combining the genes has hundreds of possible outcomes, and the trick is to find the one combination that works as a vaccine.
Using reverse genetics, researchers can clone the specific genes they need to make the vaccine instead of going through the painstaking process of identifying the perfect combination.
"Basically this technology allows us to custom-make an influenza vaccine," said Richard Webby, a vaccine researcher at St. Jude's. "There's no need to go through this laborious selection process associated with developing vaccines."
In order to create a vaccine for SARS, they will need to know which genes to clone.
The St. Jude researchers are working on another vaccine for a similar but different flu virus called H5N1, which emerged in Hong Kong in 1997 and resurfaced there in February. The virus is transmitted from birds to humans and can be deadly. They hope to begin human trials in the next few months.
The SARS virus may also be linked to birds. Researchers in China recently reported that the earliest cases developed in people who had close contact with avians such as ducks and owls.
Even in the best-case scenario, experts say the development of a vaccine will take a year.
"Generally speaking, from the time the new pathogen is discovered to the time we have a vaccine is clearly measured in years, and maybe even in decades," said Harry Greenberg, a professor of medicine at Stanford University School of Medicine.
One virologist believes trying for a SARS vaccine, or a vaccine for any other virus, is a waste. Viruses don't work alone, but work with various as-yet-unknown biological functions. Therefore, a vaccine that utilizes virus genes will never work, says Howard Urnovitz, a virologist who runs Chronic Ill Net.
"Current public health systems and officials lack the intellectual resources to understand how to create proper laboratory tests that provide an intelligent approach for containing diseases like SARS," Urnovitz said. "Therefore, I believe a vaccine against SARS is a total misappropriation of resources and will fail just like the HIV vaccine."
Other treatments for SARS have been marginally successful. Some clinicians have reported success with the drug Ribavirin, a hepatitis C treatment.
Doctors in China have also had some success eliciting an immune response in SARS victims by injecting them with plasma taken from patients who have recovered from the disease.
