SARS-Like Virus Vaccine Unlikely, Experts Say

PHOTO: An electron microscope image of a coronavirus, part of a family of viruses that cause ailments including the common cold and SARS.
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A virus similar to SARS has spread through hospitals in Europe and the Middle East, prompting fears of human-to-human transmission.

But health officials said vaccines were unlikely to play a role in controlling the outbreak, which has sickened 34 people and killed 18.

Instead, they've focused on detecting the novel coronavirus, dubbed nCoV, and have quickly isolated patients.

"Because of the challenges with developing medicines for coronaviruses, those are the most effective measures we have at this point," Gregory Hartl at the World Health Organization told ABCNews.com.

The tactic worked in the fight against SARS, or severe acute respiratory syndrome, a coronavirus that killed 775 people during a 19-month outbreak a decade ago. The virus, which spread through coughs and sneezes, vanished in May 2004.

"Once we figured out that infection control worked to stop the transmission, people started to get serious about it," said Thomas Ksiazek, who served as chief of the U.S. Centers for Disease Control and Prevention Special Pathogens Branch during the SARS outbreak. "We were pretty lucky, but the key was infection control and mindfulness."

Ksiazek, who is currently a professor in the department of pathology at the University of Texas Medical Branch in Galveston, said "mindfulness" is key once again, as a vaccine for nCoV could take years to develop and test.

"The thing that really takes time is the regulation aspect of it," he said, describing the lengthy process of proving safety and efficacy in animal models before even thinking about testing in humans.

It also takes money, and lots of it, according to Dr. Robert Atmar, who studied candidate vaccines for SARS.

"To bring a vaccine all the way through clinical development and licensure, it's going to cost tens if not hundreds of millions of dollars," said Atmar, a professor in the departments of medicine and molecular virology and biology at Baylor College of Medicine in Houston. "So part of the decision to go down that pathway will be driven by how important the pathway is.

"There was no vaccine for SARS," Atmar said. "But the public health system was able to control the infection and basically eradicate it. That might also work for this new coronavirus."

But it's more than a matter of time and money. Coronaviruses, prickly pathogens that invade the body through the respiratory tract, are notoriously difficult when it comes to vaccine development, according to Atmar. Some of the candidate vaccines for SARS caused lung damage in mice exposed to the virus.

"We don't know why. And that's the problem," said Atmar, co-author of a 2012 study published in the journal PLoS One. "The concern is that if these vaccines were to be used in people, they could end up causing harm."

So for now, experts agree that early detection and patient isolation are the best way to curb the spread of the novel coronavirus. The good news, for lack of a better term, is the virus is nowhere nearly as infectious as SARS, according to WHO's Hartl.

"One of the big differences between the novel coronavirus and SARS is the fact that SARS transmission was much better than this," Hartl said, adding that human-to-human transmission of nCoV appears to be limited to patients with prolonged contact in closed spaces, such as hospital rooms.

"From that point of view, it's a lot easier to isolate cases and stop the transmission," Hartl said.

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