COVID-19 Vaccine Candidate Shows Immune Response in Early Testing

A coronavirus disease 2019 (COVID-19) vaccine candidate has shown promise in early testing, according to a paper published by investigators from the University of Pittsburgh School of Medicine in EBioMedicine. In mouse models, the vaccine produced antibodies which may offer sufficient protection against SARS-CoV-2.

The investigational vaccine, PittCoVacc, led to a surge of antibody production within 2 weeks of administration.

The vaccine is delivered through a novel approach, known as a microneedle array. The microneedle array is a fingertip-sized patch of 400 small needles. The patch is placed like a bandage and the needles, made of protein pieces and sugar, 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,” said study author Louis Falo, MD, PhD, professor of dermatology at the University of Pittsburgh School of Medicine and UPMC, in a press release.

“And it’s actually pretty painless—it feels kind of like Velcro,” Falo added.

While the mechanism of delivery is novel, the microbiology of the vaccine is familiar. The investigators used their prior experience working with SARS-CoV-1 and MERS-CoV.

“These 2 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 study author Andrea Gambotto, MD, professor of surgery at the University of Pittsburgh School of Medicine in the press release.

The investigational vaccine’s core principles are like those behind existing influenza vaccines. While there is an experimental mRNA COVID-19 vaccine candidate under investigation, the vaccine described in EBioMedicine uses laboratory developed pieces of viral protein to induce immunity.

With its novel mechanism of deliver, however, PittCoVacc may be uniquely scalable amid the urgency of the pandemic.

The spike proteins are engineered by layering stacks of cultured cells atop each other which can be stacked further to increase yield. And after it’s manufactured, the vaccine can be stored at room temperature, eliminating the need for refrigeration during delivery or storage.

While the mice need to tracked for a longer period of time, results so far are parallel to a MERS vaccine which produced antibodies for a year. In addition, the vaccine continued to provide protection when sterilized with gamma radiation, which is considered a step toward making the product viable in human patients.

Testing in humans would usually require at least a year of study under normal circumstances, but the unique situation may lead to faster approval. A recent commentary in JAMA argued that in the circumstance of a global pandemic which has shut down society’s non-essential functions, the traditional pace of drug development is inappropriate.

The investigators are now applying for an investigational new drug approval with the US Food and Drug Administration (FDA), in hopes of starting a phase 1 human clinical trial within the coming months.

The FDA recently announced the launch of a coronavirus treatment acceleration program, indicating the sense of urgency around the pandemic.