When the coronavirus jumped from humans to mink living on farms in Denmark last year, it started to mutate in new ways—and then infect more humans. It’s a scenario that might eventually happen with other animals, and that could potentially make COVID-19 vaccines less effective or even spawn new viruses. That’s why some startups are working on COVID-19 vaccines for animals—including domestic cats.
A feline vaccine for COVID-19 could be available by the end of the year. “We are also concerned with vaccinating people, but we believe that any reservoir of the virus is one to be concerned about,” says James Hayward, CEO of Applied DNA Sciences, which will soon begin clinical trials of the new feline vaccine in New York. The company is working in partnership with Italy-based Takis Biotech, and has manufactured the first doses of a DNA-based vaccine for the trial. “It has never been demonstrated that cats can transfer the virus to humans. But even having been vaccinated, I think I would not want sleeping at my feet a reservoir of SARS-CoV.”
The virus is a zoonotic pathogen, meaning that it can go back and forth between species. When the virus ends up in a new host species, “that has new selection pressures, and that can basically change the course of evolution,” says Cock van Oosterhout, a professor of evolutionary genetics at the U.K.’s University of East Anglia. “Sometimes it can actually find a new way to then better infect the original host species, and then you get what are called spillback events.”
In a new editorial in the scientific journal Virulence, van Oosterhout and other scientists argue that the world needs to quickly do more to slow the spread of the current new variants of the virus. They focused on the need for social distancing, masks, and continued lockdowns—but also acknowledge that vaccinating animals that come into contact with humans may need to happen at some point. Some other biotech companies are now working on COVID-19 vaccines for mink.
Van Oosterhout doesn’t believe that cats need to be vaccinated yet. Cats don’t seem to get very sick from COVID-19, and don’t seem to easily spread it to other cats. There’s no evidence, yet, that they can spread it to humans. But that may change, and so it makes sense for vaccine developers to have feline vaccines ready. “With this virus, we know we need to be prepared,” he says. “And we haven’t been. That’s why we are in this absolute mess.”
The new cat vaccine uses a DNA-based system that is similar to the mRNA vaccines for humans made by Pfizer and Moderna, but can be shipped dry and doesn’t require refrigeration. Because it’s manufactured using PCR machines (the same equipment often used in testing), the technology can almost immediately begin manufacturing a new targeted vaccine if the virus mutates significantly. “Once we knew the [new DNA] sequence, we could, within hours, be manufacturing a new vaccine,” Hayward says.
This type of work can also help prepare for the next pandemic, according to van Oosterhout. “We are living in a world where emerging infectious diseases are our reality,” he says. “This is one that really hit us hard. But to say that SARS-CoV-3 might be around the corner? We don’t know. You can’t predict this, we need to be prepared. And one of the ways to prepare for this is indeed making vaccines.”