There’s been a lot of talk in recent weeks about a coronavirus vaccine, but most of that chatter has been nothing more than wishful thinking and, at best, projections or estimates. In a bit of concrete good news, researchers from the University of Pittsburgh’s School of Medicine just announced the development of a new SARS-CoV-2 vaccine that has already shown tremendous promise in mice trials.
The vaccine, administered via a small finger-tip sized patch, looks to be quite capable of neutralizing the virus. This is the first peer-reviewed research to be published on a potential novel coronavirus vaccine, an important next step in the long process towards making an effective vaccine widely available to the public. We still have a ways to go, but progress is being made.
The scientists behind this new vaccine used their knowledge of previous coronavirus strains, such as SARS, to get a jump on where to begin this time around.
“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,” explains co-senior author Andrea Gambotto, M.D., associate professor of surgery at the Pitt School of Medicine, in a press release. “That’s why it’s important to fund vaccine research. You never know where the next pandemic will come from.”
“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,” adds co-senior author Louis Falo, M.D., Ph.D., professor and chair of dermatology at Pitt’s School of Medicine and UPMC.
Unlike another potential SARS-CoV-2 vaccine, the experimental mRNA vaccine that just entered clinical trials, this vaccine (PittCoVacc) follows a much more traditional approach to vaccine construction that uses lab-produced portions of viral proteins to strengthen immunity. Flu shots operate in the same way.
The delivery method for PittCoVacc, on the other hand, is rather unique. Referred to as a microneedle array, the delivery patch contains 400 tiny needles that deliver spike proteins pieces into the skin. While the idea of 400 needles is enough to make even the most fearless among us squirm, the patch is actually quite painless. The needles are very tiny and made completely out of sugar. They simply dissolve into the skin and release the protein pieces. Researchers compare administering the vaccine to putting on a band-aid.
“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,” Dr. Falo says. “And it’s actually pretty painless — it feels kind of like Velcro.”
Other benefits of the vaccine include its high scalability and easy storage requirements. It can be stored at room temperature until needed, eliminating the need for refrigeration. Moreover, the protein pieces that drive the vaccine are created using a “cell factory,” or stacks of cultured cells specially engineered to produce the SARS-CoV-2 spike protein. The beauty of this approach is that more and more cultured cells can be stacked on top of one another to produce as many spike proteins as needed.
Scalability, or the efficiency with which a vaccine can be produced and distributed, usually isn’t a top concern among scientists, but this is anything but a usual situation.
“For most vaccines, you don’t need to address scalability to begin with,” Dr. Gambotto notes. “But when you try to develop a vaccine quickly against a pandemic that’s the first requirement.”
Within two weeks of receiving the vaccine, test mice developed a “surge” of protective antibodies against the novel coronavirus. Now, those mice haven’t been tracked for a long-term period, but researchers estimate that the mice should be immune to SARS-CoV-2 for as long as a year. A similarly designed MERS-CoV vaccine resulted in year-long immunity in a group of test mice, and this vaccine appears to be following the same route.
The PittCoVacc vaccine also retained its potency after being sterilized with gamma radiation. While that may sound like a process straight out of Incredible Hulk comics at first, gamma sterilization is a key process vaccines must go through before moving onto human trials.
Moving forward, the research team is planning on beginning human trials within the next few months.
“Testing in patients would typically require at least a year and probably longer,” Dr. Falo concludes. “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.”
The full study can be found here, published in EBioMedicine.