New York: A potential vaccine under trial against the deadly
novel coronavirus was successful when tested in mice, raising hopes of its early
Scientists of the University of Pittsburgh School of Medicine
found the vaccine PittCoVacc, short for Pittsburgh Coronavirus Vaccine, produced
antibodies specific to SARS-CoV-2 at quantities thought to be sufficient for
neutralizing the virus, when injected in the rodents.
The paper appeared in EBioMedicine, 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.
The vaccine works the same way as that of the current flu
shots. Compared to the experimental mRNA vaccine candidate that just entered
clinical trials, the vaccine follows a more established approach, using lab-made
pieces of viral protein to build immunity.
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.
When tested in mice, PittCoVacc generated a surge of
antibodies against SARS-CoV-2 within two weeks of the microneedle prick. Researchers
pointed out that the 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
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 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.