A potential vaccine for COVID-19 has been described for the first time after promising mice studies, US scientists have revealed today (2 April 2020).
Researchers at the University of Pittsburgh School of Medicine, USA, say the vaccine, delivered through a fingertip-sized patch, produces antibodies specific to SARS-CoV-2 at quantities that are believed to be sufficient for neutralising the virus.
It is hoped that human trials could begin in a few months’ time, following the promising results.
The study, outlined in the latest edition of EBioMedicine, is the first to be published after critique from fellow scientists at outside institutions that describes a candidate vaccine for COVID-19.
Co-senior author Dr Andrea Gambotto, associate professor of surgery at the Pitt School of Medicine, said their previous research into SARS-CoV in 2003 and MERS-CoV in 2014, which are closely related to SARS-CoV-2, demonstrated that a spike protein is important for inducing immunity against the virus.
Named PittCoVacc, short for Pittsburgh Coronavirus Vaccine, the vaccine uses lab-made pieces of viral protein to build immunity, similar to the way that flu vaccinations work.
A novel approach to deliver the drug – a painless microneedle array, which is a fingertip-sized patch with 400 tiny needles – was also used to increase potency.
Co-senior author Dr Louis Falo, professor and chair of dermatology at Pitt’s School of Medicine and UPMC, said: “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.”
The researchers say the system is highly scalable, with the protein pieces being manufactured by a “cell factory” that can be stacked further to multiply yield.
Purifying the protein also can be done at industrial scale by mass-producing the microneedle array using a centrifuge to spin the protein-sugar mixture into a mould.
The study shows that when PittCoVacc was tested in mice, it generated a surge of antibodies against SARS-CoV-2 within two weeks of application.
Although the mice have not been monitored long term, the research team says mice that received a MERS-CoV vaccine produced a sufficient level of antibodies to neutralise 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, they say.
Importantly, according to the research team, the SARS-CoV-2 microneedle vaccine maintains its potency even after being sterilised with gamma radiation, which is a crucial step towards making a product that is suitable for use in humans.
The researchers are applying for an investigational new drug approval from the U.S. Food and Drug Administration in the hope of starting a phase I human clinical trial in the next few months.
EBioMedicine 1 April 2020
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