The flu-like virus that exploded from China has researchers worldwide
once again scrambling to find a vaccine against a surprise health
threat, with no guarantee one will arrive in time.
Just days after Chinese scientists shared the genetic map of the
culprit coronavirus, researchers at the U.S. National Institutes of
Health had engineered a possible key ingredient for a vaccine they hope
to begin testing by April.
Scientists from Australia to France, along with a list of biotech and
vaccine companies, jumped in the race, pursuing different types of
inoculations.
And Texas researchers froze an experimental vaccine developed too
late to fight an earlier coronavirus — SARS, or severe acute respiratory
syndrome — but are pushing U.S. and Chinese authorities to give it a
try this time around. Because the new virus is a close cousin of SARS,
it just might protect, said Dr. Peter Hotez of Baylor College of
Medicine and Texas Children’s Hospital.
All that work is coming at lightning speed compared to past
outbreaks. Yet many experts agree it still may take a year — if every
step along the way goes well — for any vaccine to be ready for
widespread use. That’s if it’s even needed by then.
Globally, more than 28,000 people are infected and the death toll
climbed past 560. The overwhelming majority are in China, but more than
200 people with the illness have been reported in over two dozen other
countries.
For now, health officials are isolating the sick to fight spread of
the virus, which causes fever, cough and in severe cases pneumonia. With
no specific treatment, some doctors also are experimenting with
antiviral medicines developed for other conditions.
“Ours is already manufactured and could take off pretty quickly,”
said Hotez, who created the earlier SARS vaccine with Texas Children’s
colleague Maria Elena Bottazzi. But “there’s still no road map for what
you do to make a vaccine in the midst of a devastating public health
outbreak.”
NIH specialists say rather than chasing outbreaks, it’s time to
pursue prototype vaccine designs that could work for entire virus
families, ready to be pulled off the shelf at the first sign of a new
disease.
“We have the technology now. It’s feasible from an engineering and
biological standpoint,” said Dr. Barney Graham, deputy director of the
National Institute of Allergy and Infectious Diseases’Vaccine Research
Center. Without that step, “we’re going to be at risk for new
pandemics.”
A FASTER VACCINE RECIPE
Traditionally, making vaccines required first growing lots of virus
in a lab. The NIH team is pursuing a newer and far faster method: Simply
use a piece of the virus’ genetic code, called messenger RNA or mRNA,
that instructs cells to make a particular protein.
“We think of RNA as the software of life,” said Dr. Tal Zaks, chief
medical officer of Moderna Inc., which is developing mRNA vaccines for
other diseases and working with NIH on the new coronavirus.
Inject the right piece and “you’ve taught the body to make its own
medicine,” he explained. As cells produce just that protein, the immune
system learns to recognize it, primed to attack if the entire virus ever
comes along.
The target: A protein aptly named “spike” that lets the virus bind to
cells. It studs the surface of coronaviruses — the new one as well as
its cousins SARS, which erupted in China in 2002 and spread to 26
countries, and MERS, or Middle East respiratory syndrome, which emerged
in 2012.
Graham’s team zeroed in on the RNA responsible for the new virus’
production of spike and then — because prior research showed the protein
can change shape — engineered a more stable version of it.
Moderna is manufacturing samples of the synthetic mRNA vaccine for
NIH to use in animal studies and, hopefully within three months,
first-stage safety tests in people. If further testing proves it really
works, the hope is scientists could simply swap in a new spike code if
another coronavirus comes along.
That’s important because after three such outbreaks in less than 20
years, “this is not the last,” predicted Dr. Mark Denison, a virologist
at Vanderbilt University Medical Center. It’s key to find vaccine
“strategies that go after these unique things common to every
coronavirus.”
WHAT ELSE IS IN THE PIPELINE
Inovio Pharmaceuticals is pursuing a similar approach with synthetic
DNA, and recently reported promising results from first-stage testing of
a MERS vaccine. It’s collaborating with a Chinese company, Beijing
Advaccine, in hopes of being able to test a new vaccine candidate in
China later this year.
In France, researchers at the Pasteur Institute are piggybacking on
the tried-and-true vaccine against measles. They’ve had some early
success mixing genetic material from other viruses into that vaccine,
and now hope to put the immune system on alert against this new
coronavirus in the same way.
“The work we’re doing now involves making a vaccine against measles
but re-engineered in the sense that it has antigens from the new
coronavirus,” said virologist Frederic Tangy, head of Pasteur’s vaccine
innovation department.
What about Hotez’s old SARS vaccine? In that case a piece of the
spike protein was genetically engineered and grown in a lab, a classic
vaccine technology compared to the newer and less proven Moderna and
Inovio approaches. The Texas researchers showed the vaccine protected
animals but in 2016 ran out of money for further testing and froze what
was left. Every six months, Hotez thaws a small sample to make sure it’s
still usable.
CHASING OUTBREAKS
Past outbreaks are full of such missed opportunities: There’s no
commercial vaccine for MERS even though illnesses still occur. The birth
defect-causing Zika outbreak was ending by the time experimental shots
were ready to test.
The bright spot: Ebola vaccines. Some candidates began early testing
during the massive Ebola epidemic in West Africa in 2014-2016, although
the outbreak waned before scientists had proof they worked. But
authorities and vaccine companies kept up the research, and by 2018
shots were ready to help tamp down an outbreak still smouldering in
Congo.
The World Health Organization will meet next week to identify
promising drug and vaccine candidates for the new coronavirus and
fast-track their development, much like happened with Ebola.
“To put it bluntly, we’re shadow boxing,” said WHO Director-General
Tedros Adhanom Ghebreyesus. “We need to bring this shadow out into the
light so that we can attack it properly.”
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