The
Chinese mainland has approved human trials of four vaccines for the
H7N9 bird flu virus as authorities struggle to contain the deadliest
outbreak of the disease to hit the country.
In January alone, the virus killed 79 people. Among the latest
victims were a 23-year-old woman and her three-year-old daughter in
Yunnan province.
The trials would comprise several phases, Xinhua reported on
Thursday. Scientists began testing potential H7N9 vaccines on animals
soon after the first human case was reported in March 2013.
Researchers were initially hopeful that a human vaccine would be
available “soon” but success has been hampered by technical, business
and regulatory hurdles.
Dr Shi Yi, viral infection researcher with the Chinese Academy of
Sciences’ Institute of Microbiology, described H7N9 as a “serial killer
with two faces”.
Shi’s team, which studied the viral strain after the 2013 outbreak,
was puzzled by the virus’ ability to spread and kill. The virus in
humans spread quickly too, but was far less lethal, Shi said.
It affects the upper respiratory tract – which allows it to be
transmitted easily through saliva – but usually spares the lungs. Other
deadly bird flu viruses, such as H5N1, usually affect the lungs and
cause great discomfort for their victims but spread less effectively.
H7N9 targeted both the upper throat and the lungs, enabling it to not
only spread quickly but also to inflict lethal damage on its victims,
Shi said.
The unique nature of this viral strain posed technological challenges
to developing a human vaccine for it, but there were also other
obstacles, Shi said.
With the H7N9 outbreaks being relatively mild in recent years,
commercial interest to develop the vaccine had been limited as there was
little demand, he said.
“It is hard to persuade a vaccine company [to invest] without the promise of profit,” Shi said.
A publicly available vaccine could take eight to 20 years, according to mainland media reports.
“We should work harder to speed up the pace of vaccine development
because it is the only method to save a large population from a possible
outbreak of the deadly virus,” Shi said.
Professor Zhou Demin, dean of Peking University’s School of
Pharmaceutical Sciences, said he felt sorry for patients who were
suffering or dying from diseases that could be cured by drugs under
development.
Zhou’s team published a study last year on Science, a US
academic journal, about a groundbreaking technology to quickly develop
vaccines for almost any virus and effectively cure ongoing infections.
Since then, patients with HIV/Aids and other presently incurable diseases have sought him out in his office frequently, he said.
But the technology requires at least three to five years to pass
regulatory checks before it can be tested on humans, according to Zhou.
“It is really sad to watch people dying with a possible cure in
hand,” he said. “But we are scientists, not doctors. All we can do is
communicate with government regulators to accelerate approval for new
drugs.”
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