Controversial Bird-Flu Study Published: Simple Mutations Could Cause H5N1 Pandemic

On Wednesday, the journal Nature published the first of the controversial bird flu studies blocked from publication by the U.S. government in December after it deemed a revised version of the study did not pose a threat to national security.

The U.S. government was weary of the studies because it believed bioterrorists could use the information to create and release an easily-transmissible strain of the virus. Both of the papers were revised and in March, National Science Advisory Board for Biosecurity recommended that the papers be published.

Bird flu, also known as H5N1, is deadly in humans, but so far it is only transmissible through close contact between birds and humans, unlike the seasonal flu, which can be spread from person to person via the air. Scientists were skeptical as to whether bird flu could mutate into a strain capable of spreading between humans, but the new study shows that with a few simple mutations, it can.

"H5N1 viruses remain a significant threat for humans as a potential pandemic flu strain," Yoshihiro Kawaoka, study author and professor of virology at the University of Wisconsin-Madison, told HealthDay. "We have found that relatively few mutations enable this virus to transmit in mammals."

Flu viruses constantly mutate by exchanging genes with other flu strains, which is why flu shots are administered every year. The researchers hoped that by studying how the bird flu virus mutates they could create an effective vaccine to stop a potential pandemic before it spread.

"Stockpiling H5N1 vaccines and antivirals will be important for pandemic preparedness," Kawaoka said. "Just as for a seasonal flu vaccine, it will be important for an H5N1 vaccine to be made to a closely related virus, so knowing which mutations may confer transmissibility will help prioritize vaccine candidates."

The World Health Organization currently recognizes 586 bird flu infections in humans human, mostly in Asia, and 346 deaths, which equals a fatality rate of 60 percent and makes a pandemic potentially devastating. The 1918 Spanish flu, which killed 50 million people over the course of a year, had a fatality rate of 3 percent. The seasonal flu has a fatality rate between 0.001 and 0.02 percent.

"There are people who say that bird flu has been around for 16, 17 years and never attained human transmissibility and never will," Malik Peiris, virology professor at the University of Hong Kong who wrote an editorial accompanying the study, told Fox News. "What this paper shows is that it certainly can. That is an important public health message -- we have to take H5N1 seriously. It doesn't mean it will become a pandemic, but it can."

In order to study how long it would take a mutated flu virus to become transmissible to humans, the researchers combined the bird flu virus is the H1N1 swine flu virus that caused a pandemic in 2009 and administered it to ferrets, an animal the responds to the flu in a similar way as humans. They found that after just four mutations within the ferrets the virus was able to spread between them, something it was previously unable to do.

Some scientists, however, think purposefully creating such a dangerous virus is irresponsible.

"This is work that creates new biological threats," Richard Ebright, a molecular biologist at Rutgers University, told CBS News. "These viruses are dangerous and the ones that will come later (with further research) will be more dangerous."

But researchers said that fears over the modified virus are unfounded.

"It doesn't necessarily mean that just because this virus transmitted in ferrets, it will 100 percent transmit in humans, but it's as close as we can get," Peiris told the Daily Mail. "It lost a lot of its [harmfulness] in ferrets, maybe because of the H1N1 backbone."

A second study conducted a similar test, though the results are not yet known. That study will be published in the journal Science later this year.

Many doctors applauded the papers release, saying it's prudent to understand that the virus can change and mutate.

"Publication makes us safer because we know what to look out for now," Dr. Bruce Hirsch, an infectious diseases specialist at North Shore University Hospital, told HealthDay. 'This can help facilitate preventive strategies and can eventually lead to more effective vaccine development and antiviral therapy."