Researchers working on a potential vaccine against the new coronavirus causing the COVID-19 pandemic are exploring the use of a fingertip-sized skin patch for delivery.
The product being developed by the University of Pittsburgh Medical Center and the University of Pittsburgh has been tested in mice and appears to produce antibodies specific to SARS-CoV-2 at quantities thought to be enough to neutralize the virus.
The report, which appeared in EBioMedicine, is touted as the first study on a potential COVID-19 vaccine to be published after a critique from fellow scientists at outside institutions.
“Here, we demonstrate the rapid development of MNA [microneedle array] SARS-CoV-2 S1 subunit vaccines and their promising immunogenicity in mice developed using our evolving experience with MERS-CoV vaccines and MNAs,” the researchers write. “First, we evaluate the immunogenicity of trimeric form of MERS-S1 subunit vaccines delivered subcutaneously by traditional needle injection, or intracutaneously by MNAs. Driven by the promising immunogenicity of MNA-MERS-S1 vaccines and the urgent need to respond to the recent coronavirus pandemic (COVID-19), we rapidly (within four weeks of the identification of the SARS-CoV-2 S1 sequence) designed and produced MNA SARS-CoV-2 S1 vaccines and tested their immunogenicity in mice.”
The authors note that the coronavirus spike (S) protein, a characteristic structural component of the viral envelope, is considered a key target for vaccines for the prevention of infection from those viruses. The preclinical immunogenicity of MERS-CoV vaccines were tested in mice and were delivered both subcutaneously by traditional needle injection or intracutaneously by dissolving MNAs. Virus-specific immunoglobulin antibodies in the serum and virus neutralization assays were used to evaluate the effect.
“MNA delivery of coronaviruses-S1 subunit vaccines is a promising immunization strategy against coronavirus infection,” the authors add.
“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," explained co-senior author Andrea Gambotto, MD, associate professor of surgery at the University of Pittsburgh School of Medicine.
The MNA is a fingertip-sized patch of 400 tiny needles that deliver spike protein pieces into the skin, where the immune reaction is the strongest. Researchers report that the patch goes on like a bandage, and the needles, which are made entirely of sugar and protein pieces, 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,” noted co-senior author Louis Falo, MD, PhD, professor and chair of dermatology at Pitt’s School of Medicine and UPMC.
The authors are applying for an investigational new drug approval from the FDA in anticipation of starting a phase I human clinical trial in the next few months. That is estimated to take a year or longer.
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