University of Pittsburgh School of Medicine scientists announced a
potential vaccine against SARS-CoV-2, the new coronavirus causing the COVID-19
pandemic. When tested in mice, the vaccine, delivered through a fingertip-sized
patch, produces antibodies specific to SARS-CoV-2 at quantities thought to be
sufficient for neutralizing the virus.
The paper appeared in EBioMedicine, which is published
by The Lancet, and is the first study to be published
after critique from fellow scientists at outside institutions that describes a
candidate vaccine for COVID-19. The researchers were able to act quickly
because they had already laid the groundwork during earlier coronavirus
epidemics.
“We had previous
experience on SARS-CoV in 2003 and MERS-CoV in 2014. These two viruses, which
are closely related to SARS-CoV-2, teach us that a particular protein, called a
spike protein, is important for inducing immunity against the virus. We knew
exactly where to fight this new virus,” said co-senior author Andrea Gambotto,
M.D., associate professor of surgery at the Pitt School of Medicine. “That’s
why it’s important to fund vaccine research. You never know where the next
pandemic will come from.”
“Our ability to
rapidly develop this vaccine was a result of scientists with expertise in
diverse areas of research working together with a common goal,” said co-senior
author Louis Falo, M.D., Ph.D., professor and chair of dermatology at Pitt’s
School of Medicine and UPMC.
Compared to the
experimental mRNA vaccine candidate that just entered clinical trials, the
vaccine described in this paper — which the authors are calling PittCoVacc,
short for Pittsburgh Coronavirus Vaccine — follows a more established approach,
using lab-made pieces of viral protein to build immunity. It’s the same way the
current flu shots work.
The researchers
also used a novel approach to deliver the drug, called a microneedle array, to
increase potency. This array is a fingertip-sized patch of 400 tiny needles
that delivers the spike protein pieces into the skin, where the immune reaction
is strongest. The patch goes on like a Band-Aid and then the needles — which
are made entirely of sugar and the protein pieces — simply dissolve into the
skin.
“We developed
this to build on the original scratch method used to deliver the smallpox
vaccine to the skin, but as a high-tech version that is more efficient and
reproducible patient to patient,” Falo said. “And it’s actually pretty painless
— it feels kind of like Velcro.”
The system also
is highly scalable. The protein pieces are manufactured by a “cell factory” —
layers upon layers of cultured cells engineered to express the SARS-CoV-2 spike
protein — that can be stacked further to multiply yield. Purifying the protein
also can be done at industrial scale. Mass-producing the microneedle array
involves spinning down the protein-sugar mixture into a mold using a
centrifuge. Once manufactured, the vaccine can sit at room temperature until
it’s needed, eliminating the need for refrigeration during transport or
storage.
“For most
vaccines, you don’t need to address scalability to begin with,” Gambotto said.
“But when you try to develop a vaccine quickly against a pandemic that’s the
first requirement.”
When tested in
mice, PittCoVacc generated a surge of antibodies against SARS-CoV-2 within two
weeks of the microneedle prick.
Those animals
haven’t been tracked long term yet, but the researchers point out that mice who
got their MERS-CoV vaccine produced a sufficient level of antibodies to
neutralize the virus for at least a year, and so far the antibody levels of the
SARS-CoV-2 vaccinated animals seem to be following the same trend.
Importantly, the
SARS-CoV-2 microneedle vaccine maintains its potency even after being
thoroughly sterilized with gamma radiation — a key step toward making a product
that’s suitable for use in humans.
The authors are
now in the process of applying for an investigational new drug approval from
the U.S. Food and Drug Administration in anticipation of starting a phase I
human clinical trial in the next few months.
“Testing in
patients would typically require at least a year and probably longer,” Falo
said. “This particular situation is different from anything we’ve ever seen, so
we don’t know how long the clinical development process will take. Recently announced
revisions to the normal processes suggest we may be able to advance this
faster.”
Source: https://myfusimotors.com/2020/04/04/covid-19-vaccine-candidate-shows-promise-research-shows/
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