COVID-19 vaccine packed into skin patch shows promise in mice

The companies entering the race to develop a COVID-19 vaccine will not only have to prove efficacy quickly, they’ll also have to figure out how to scale up production in time to help stem the current epidemic. Researchers at the University of Pittsburgh School of Medicine say they’ve made progress on both fronts with their new COVID-19 vaccine candidate.

The team developed a vaccine that can be delivered into the skin with a Band-Aid-like patch made of 400 tiny needles. When they tested it in mice, the vaccine produced antibodies to fend off the virus within two weeks, they reported in the journal EBioMedicine. The researchers are now applying for an investigational new drug designation from the FDA in the hopes of starting a phase 1 clinical trial shortly, they said in a statement.

The Pitt invention builds off discoveries the researchers made during the SARS-CoV outbreak of 2003 and the emergence of MERS-CoV a few years ago. COVID-19 shares a “spike” protein with those earlier viruses. The new vaccine, called PittCoVacc, contains pieces of that protein. It’s designed to spark an immune reaction against the virus without actually causing any symptoms of it—a similar mechanism of action to the flu vaccine.

The microneedles that deliver the vaccine are made of sugar, making the patch easy to mass produce and to store with no need for refrigeration, the researchers explained. The protein particles are made in stacks of cultured cells that can be built up as needed to meet demand. "For most vaccines, you don't need to address scalability to begin with," said co-senior author Andrea Gambotto, M.D., associate professor of surgery at Pitt's School of Medicine, in the statement. "But when you try to develop a vaccine quickly against a pandemic that's the first requirement."

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The Pitt team’s approach differs from that taken by the current front-runners in the COVID-19 vaccine race. In late February, Moderna started clinical trials of a vaccine based on messenger RNA (mRNA). The vaccine, called mRNA-1273, encodes the spike protein, thereby instructing the body’s cells to express that protein in a way that sparks an immune response. Earlier this week, Sanofi and Translate Bio announced plans to develop an mRNA vaccine against the coronavirus. Pfizer and BioNTech are also working on an mRNA vaccine.

Johnson & Johnson, meanwhile, is developing a vaccine of its own, saying last week it was investigating five different virus constructs to figure out the best approach. It selected its top candidate earlier this week and is working with the U.S. Biomedical Advanced Research and Development Authority to get it ready for clinical trials by September.

The Pitt team can’t say for certain whether their vaccine candidate produces long-lasting protection against COVID-19. But a similar vaccine they made against MERS-CoV produced enough antibodies in mice to protect them from that virus for a year. The antibody levels they’ve tracked in the mice that received the COVID-19 vaccine are following a similar trend, they said.