COVID-19 Vaccine Shows Early Promise

Initial tests of a potential COVID-19 vaccine — PittCoVacc — shows it produces antibodies in sufficient amounts to combat the virus.

PittCoVac cis delivered into the skin through a fingertip-sized patch of microscopic needles (UPMC).

Researchers from the University of Pittsburgh School of Medicine have announced a potential vaccine for the novel coronavirus — SARS-CoV-2 — that causes COVID-19. The vaccine — named PittCoVacc, short for Pittsburgh Coronavirus Vaccine — is delivered into the system via a fingertip-sized patch of needles made from sugar and proteins, and produces enough antibodies to fight SARS-CoV-2 and neutralise the virus.

Thus far, the results published in the journal EBioMedicine — part of the Lancet family of publications — represent tests carried out on mice, so should be viewed with some caution. Despite this, the study represents the first to describe a candidate vaccine for COVID-19 published after critique from independent scientists.

The team at the University of Pittsburgh were able to hit the ground running on a vaccine to tackle the pandemic because they have experience in dealing with previous coronavirus epidemics.

Andrea Gambotto, M.D., associate professor of surgery at the Pitt School of Medicine, says: “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.”

Gambotto also points out that the fact the team has able to get a significant headstart in tackling the COVID-19 crisis is a fantastic example of why governments across the globe should prioritise such research: “That’s why it’s important to fund vaccine research. You never know where the next pandemic will come from.”

Louis Falo, M.D., Ph.D., professor and chair of dermatology at Pitt’s School of Medicine and UPMC, co-senior author on the paper, echoes the statement: “Our ability to rapidly develop this vaccine was a result of scientists with expertise in diverse areas of research working together with a common goal.”

Using old and new techniques to tackle COVID-19

Whilst there are other vaccines in development — such as an mRNA vaccine candidate currently being tested — some take an experimental approach in order to tackle COVID-19. PittCoVacc takes a more established approach by using pieces of viral protein created in a lab in order to build immunity. This method is analogous to the way the current generation of flu vaccines work.

What is more novel about PittCoVacc is the way the drug is delivered into a patients’ system. A microneedle array consisting of a tiny patch of 400 tiny needles — made entirely of sugar and the protein pieces — in a fingertip-sized patch. The patch goes on like a Band-Aid with the needles simply dissolving into the skin.

Not only does this increase the potency of the vaccine, but it also allows medical professionals to deliver the spike protein pieces into the skin where the immune reaction is strongest.

Falo says: “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.” For patients who worry about needles, he adds: “And it’s actually pretty painless — it feels kind of like Velcro.”

Scaling up the vaccine to tackle a global crisis

The fact that the COVID-19 crisis is a global pandemic means that for any vaccine to be effective it has to be distributable in large numbers almost immediately. Thus, another major advantage of the system that the Pittsburgh team have developed is the fact it is eminently scalable.

Gambotto says: “For most vaccines, you don’t need to address scalability, to begin with, but when you try to develop a vaccine quickly against a pandemic that’s the first requirement.”

Hundreds of millions of COVID-19 vaccine doses will need to be produced worldwide, so the researchers made sure upfront that their process was scalable. (UPMC)

The key to this scalability lies in the fact that the protein pieces are manufactured by layers upon layers of cultured cells engineered to express the SARS-CoV-2 spike protein —a so-called ‘cell factory.’ This cell factory can be stacked further to increase the yield. Plus, purifying the protein also can be carried out at an industrial scale.

Mass-producing the microneedle array involves spinning down the protein-sugar mixture into a mold using a centrifuge. The vaccine can then sit at room temperature until it’s needed, thus eliminating the need for refrigeration during transport or storage.

Another positive is that the vaccine retained its potency after it was treated with gamma radiation, meaning that it is viable after sterilisation and thus suitable for human use.

Consider with caution — there’s a long way to go yet

Whilst the initial results are promising, the vaccine generated a surge of antibodies against SARS-CoV-2 within two weeks of the microneedle prick, it has thus far only been tested on mice. Additionally, the subjects haven’t been tracked long term as of yet.

The researchers use FDA Good Manufacturing Practice to produce vaccines suitable for human clinical trials (UPMC)

Despite this, the team say that mice who received a similar MERS-CoV vaccine produced a sufficient level of antibodies to neutralize the virus for at least a year. They add that, so far, the antibody levels of the SARS-CoV-2 vaccinated animals seem to be following the same trend.

The authors are now in the process of applying for new drug approval from the U.S. Food and Drug Administration in anticipation of starting the first phase of human clinical trials in the next few months.

Falo says: “Testing in patients would typically require at least a year and probably longer.

“This particular situation is different from anything we’ve ever seen, so we don’t know how long the clinical development process will take.