COVID-19 / VIRUS Bloomberg Businessweek March 16, 2020
59to develop a vaccin
○It’s a basic rule of medical research: Before you
inject anything into humans, conduct experiments
on animals—frequently mice—to determine whether
treatments are safe and effective. In the race to
develop a vaccine for the new coronavirus, however,
your everyday mouse won’t do. While mice have
a gene similar to the one scientists believe allows
the virus to affect humans, researchers think those
mice don’t exhibit the symptoms that make the ill-
ness so deadly for people. “You can infect them, but
they have very little, if any, clinical disease,” says
Richard Bowen, a professor of veterinary medicine
at Colorado State University.
That’s great if you’re a mouse, but not if you’re a
researcher. So scientists often seek mice that have
been genetically modified with a humanized gene,
called ACE2, that makes the virus more virulent—
and thus better for studying its effects. As Covid-19
spreads around the world, though, it’s almost impos-
sible to find transgenic ACE2 mice needed to study
the virus. There are no global statistics on availability
of those animals, but several vendors of transgenic
mice say they have none available, and research-
ers expect it will take weeks or months to develop a
sufficient supply. “Almost nobody has these mice in
a viable colony now,” says Stanley Perlman, a pro-
fessor at the University of Iowa’s medical school.
“Everybody I know is trying to find them.”
Secondary bacterial infections represent an espe-
cially pernicious threat because they can kill criti-
cal respiratory tract stem cells that enable tissue to
rejuvenate. Without them, “you just can’t physically
repair your lungs,” Taubenberger says. Damaged
lungs can starve vital organs of oxygen, impairing
the kidneys, liver, brain, and heart. “When you get
a bad, overwhelming infection, everything starts to
fall apart in a cascade,” says David Morens, senior
scientific adviser to the director of the National
Institute of Allergy and Infectious Diseases. “You
pass the tipping point where everything is going
downhill, and at some point you can’t get it back.”
That tipping point probably also occurs earlier
in older people, as it does in experiments with
older mice, says Stanley Perlman, a professor of
microbiology and immunology at the University
of Iowa, who’s studied coronaviruses for 38 years.
Still, even healthy younger adults have succumbed
to the illness. Li Wenliang, the 34-year-old
ophthalmologist who was one of the first to warn
about the coronavirus in Wuhan, died last month
after receiving antibodies, anti virals, antibiotics,
and oxygen and having his blood pumped through
an artificial lung. Some people may be more
susceptible, possibly because they have a greater
abundance of the distinctly shaped protein receptors
in their respiratory epithelial cells that the virus
targets, Taubenberger says. It’s also possible certain
individuals have some minor immunodeficiency or
other host factors that relate to underlying illnesses.
—Jason Gale○ Share of coronavirus
patients who become
critical6%
A mouse from
the line donated
by PerlmanIt’s not possible to keep mice on hand for every
potential disease. Despite short outbreaks of
coronavirus- caused illnesses such as SARS, which
paralyzed China, Hong Kong, and other parts of Asia
for months in 2003, most scientists stick with more
lucrative opportunities in cancer, hepatitis, and
other chronic ailments that require different variet-
ies of lab animals. “Research follows trends, and at
the moment people are mainly focusing on oncology
and metabolic disorders,” says Kader Thiam, who
oversees genetically modified mice at GenOway SA,
a lab animal developer in Lyon, France.
The Jackson Laboratory, a nonprofit in Maine that
supplies animals to medical researchers, sells more
than 11,000 varieties of mice. But when the corona-
virus started making headlines in January, Jackson
didn’t have any with the necessary gene. As orders
began flowing in, the Jackson crew started scour-
ing medical literature for people who’d worked with
humanized mice and might donate some for breed-
ing. They found Perlman, a coronavirus specialist
who had used transgenic mice in the fight against
SARS. Perlman didn’t have any live mice, because
a decade ago he decided his lab couldn’t afford to
maintain them, but he’d extracted sperm samples
just in case. Last month he sent those frozen rem-
nants of the discontinued colony to Jackson, which
is using them to impregnate mice and begin a