WASHINGTON – Scientists proposed developing a more potent strain of the deadly H7N9 bird flu Wednesday to examine how mutant forms might spread among humans, a topic that has stoked global alarm in the past.
The announcement came a day after Chinese scientists reported the first likely case of person-to-person transmission of the H7N9 virus, which has killed 43 of the 134 people infected since March, according to official figures.
U.S. health authorities said any new H7N9 experiments that seek U.S. funding would undergo a new, strict safety review, after concerns over such research on another bird flu infection, H5N1, in December 2011 raised fears that terrorists could unleash a virulent lab-grown strain and cause mass deaths.
Those concerns led to a year-long halt to the research being led by Ron Fouchier of Erasmus Medical Center in the Netherlands and colleagues in Wisconsin. That voluntary moratorium was lifted this year by a group of 40 scientists around the world.
Fouchier said his lab has resumed work on an engineered H5N1 virus, but that U.S. laboratories have not and are awaiting a final decision by American health authorities, expected in the coming weeks.
The latest proposal by Fouchier and 21 colleagues in Hong Kong, Britain and the United States is to examine how H7N9 may spread among mammals and become more potent and drug-resistant. This “gain of function” research is “necessary and should be done” to better understand how the virus could act in the future, Fouchier and his colleagues said in a letter published in the journals Science and Nature. “To fully assess the potential risks associated with these novel viruses, there is a need for additional research,” said the letter.
The research is urgent because the H7N9 virus has some characteristics in common with human flu viruses and others such as H5N1 that have adapted to transfer from birds to mammals, Fouchier and his colleagues wrote.
H7N9 also shows signs of resistance to the main medical treatment, Tamiflu, and other neuraminidase inhibitors, which “could increase the risk of serious outcomes,” they wrote.
Research has shown that H7N9 could spread among ferrets in close contact, and may be able to transmit in people under certain conditions.
“Because the H7N9 virus has acquired the ability of limited airborne transmission under natural circumstances, many experts think the threat posed by H7N9 is higher than for H5N1,” Fouchier said in an interview. “As a consequence, it is possible that some people think that H7N9 research is more urgent.”