University of Pittsburgh School of Medicine scientists announced a potential vaccine against SARS-CoV-2. According to their paper, published today in EbioMedicine, 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.
"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.
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.
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," co-senior author Louis 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.
The authors are now in the process of applying for an investigational new drug approval from the FDA in anticipation of starting a Phase I 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."