CHARLOTTESVILLE, Va. — Despite millions already receiving the COVID-19 vaccine, many worry if their version will defend against new coronavirus strains. Luckily, scientists are closing in on a potential universal answer to the pandemic. Researchers in Virginia say a new vaccine which may protect against existing and future strains is showing promising results in animal testing. Even more encouraging, the process which creates this formula could make the vaccine’s production as cheap as $1 a dose.
UVA Health’s Steven Zeichner, MD, PhD, and Virginia Tech’s Xiang-Jin Meng, MD, PhD, have successfully tested their vaccine on pigs. According to the team, the drug prevents pigs from becoming sick due to porcine epidemic diarrhea virus (PEDV) — a pig version of coronavirus.
Researchers used an innovative process to make the treatment, which Zeichner says opens the door for creating universal COVID vaccines. Such a drug could conceivably stop strains responsible for this pandemic, previous virus outbreaks (like SARS), and even strains causing the common cold.
The Virginia scientists add their vaccine also offers several advantages which have been hindering the current worldwide rollout. Most importantly, the new drug would be easier to store and transport to more remote areas of the world. Researchers say it can also be produced in mass quantities using existing vaccine-manufacturing facilities. What makes this potential drug so unique, Zeichner explains, is their new platform invented for rapid vaccine development.
“Our new platform offers a new route to rapidly produce vaccines at very low cost that can be manufactured in existing facilities around the world, which should be particularly helpful for pandemic response,” the UVA researcher says in a university release.
Using E. coli to beat COVID-19
Zeichner’s new platform synthesizes DNA which directs the body to produce a piece of the virus. From there, the virus portion can instruct the immune system how to better respond to the virus cells.
The DNA is inserted into another small group of DNA, plasmids, that are able to reproduce inside bacteria. The plasmid then enters the bacteria, telling it to deploy proteins along its surface. Scientists relied on E. coli bacteria during this experiment.
While E. coli usually has a bad reputation, there are strains beneficial to human health. In this instance, the E. coli has had many of its genes deleted. Removing them increases the immune system’s ability to recognize the vaccine antigens on the surface of this bacteria.
To create this type of vaccine, scientists grow the bacteria expressing these antigens in a fermenter. The device is very similar to the common machines brewers use. Once the process is complete however, researchers kill these bacterium with a low concentration of formalin.
“Killed whole-cell vaccines are currently in widespread use to protect against deadly diseases like cholera and pertussis. Factories in many low-to-middle-income countries around the world are making hundreds of millions of doses of those vaccines per year now, for a $1 per dose or less,” Zeichner explains. “It may be possible to adapt those factories to make this new vaccine. Since the technology is very similar, the cost should be similar too.”
The study notes that this process isn’t just cheap, it’s also very fast. The entire process, from identifying a vaccine target, to creating gene-deleted bacteria, takes between two and three weeks.
Taking on COVID’s infamous ‘spike’ protein
To tackle coronavirus, Zeichner and Meng’s vaccine targets an unusual foe — the virus’s spike protein. This “viral fusion peptide” is a universal feature among all coronavirus strains. In the case of SARS-CoV-2, the virus causing COVID-19, this protein attaches to receptors on human cells and cuts its way inside to hijack the cell functions. Researchers examined thousands of patients and find this spike doesn’t seem to differ at all in SARS-CoV-2 cases.
The team created two vaccines, one to protect against COVID and the other to fight off PEDV. While both of these sicknesses are coronaviruses, scientists consider them “distant relatives.”
Despite this distant connection, they both share many of the amino acids that form the fusion peptide. In pigs with PEDV, the illness causes diarrhea, vomiting, and high fever. This has led to a tremendous burden on pig farmers worldwide after first appearing among U.S. pigs. To date, the virus has killed nearly 10 percent of America’s pig population.
Researchers say studying PEDV allows them to see how their vaccines work against a coronavirus in its native host — in this case, pigs. Other COVID vaccines have studied SARS-CoV-2 infecting non-native hosts, like monkeys, hamsters, or mice. Another benefit of using pigs is they are physiology and immunology similar to people. Aside from primates, they are likely the closest animal model to humans that researchers have.
The results reveal both vaccines, for SARS-CoV-2 and PEDV, protected the pigs from developing symptoms of PEDV. Although the vaccines did not prevent a coronavirus infection, they did keep the animals from experiencing a severe illness. The two vaccines also appear to prime the body to put up a stronger fight against various coronavirus strains.
Moving the testing into humans
The Virginia team suspects, if both of their vaccines protect pigs against PEDV, then their SARS-CoV-2 vaccine will likely do the same against COVID-19 in humans. To prove this however, scientists will need to move their experiments into human trials. After that, they’ll need approval from the Food and Drug Administration for widespread use. In the meantime, study authors say they are happy with their initial findings, which may soon lead to a universal COVID vaccine.
“XJ is just an amazing collaborator and a wonderful scientist. And he is incredibly generous with his time and the resources he has available,” Zeichner concludes. “If UVA and Virginia Tech scientists can work together to try to do something positive to address the pandemic, then maybe there is some hope for collaboration and cooperation in the country at large.”
The study appears in the journal PNAS.