Zoo animals in Canada are getting vaccinated for SARS-CoV-2, the virus that causes COVID-19. On March 8, Assiniboine Park Zoo in Winnipeg became the first zoo to administer shots from Zoetis, a U.S.-based animal health company that has developed vaccines for diseases including avian influenza. 

The Canadian Food Inspection Agency said in an email that the vaccine is in “limited supply” and approved on a case-by-case, emergency, experimental basis. Zoetis spokesperson Christina Lood said the company is donating vaccines to Canadian zoos on a first-come, first served basis, and is splitting the shipment of 900 vaccines between six zoos. A full course of the vaccine is two doses given three weeks apart.

Zoetis began developing the vaccine in 2020, as domestic dogs and cats around the world began testing positive for the virus or its antibodies. Rollout began in July 2021, when the company donated 11,000 doses to zoos, academic institutions and other organizations in the U.S. Spokesperson Christina Lood said via email that the vaccine has since been used in multiple countries for over 300 mammalian species. No zoo animals have tested positive for SARS-CoV-2 in Canada, but they have died of COVID-19 elsewhere.

The Zoetis vaccine uses technology that is different from the human vaccines best known in Canada. It does not use mRNA technology like the Pfizer or Moderna vaccines, or viral vector technology like the ones developed by Janssen and AstraZeneca. Instead, said Lood, it’s similar to the Novavax vaccine, which Health Canada authorized for humans in mid-February.

According to the Health Canada information sheet on Novavax, this type of vaccine is made by inserting a small piece of the genetic code of the SARS-CoV-2 virus into another cell. “The code stimulates the host cell to develop the COVID-19 ‘spike’ protein, which is known to stimulate immune cells. The cells then act like factories, building large quantities of the protein. The protein is extracted, purified and used as the active ingredient in the vaccine.” It’s known as “subunit recombinant” or “protein subunit” technology. 

When the vaccine is administered, the immune system of the human or animal recipient experiences the proteins as foreign. It then “begins making T-lymphocytes and antibodies. If we’re ever infected in the future, memory cells will recognize and fight the virus,” said the Health Canada site. Lood noted that the Zoetis vaccine formula is designed specifically for animals. While the virus — or antigen given off by that virus — is the same as in human vaccines, she said, the other ingredients in animal vaccines vary based on species. 

Assiniboine Park is planning to vaccinate 55 animals, including tigers, snow leopards and other big cats, as felines have been shown to be particularly vulnerable to COVID-19. So have primates, which is why the zoo’s white-handed gibbons and squirrel monkeys are also on its list. 

In February, the Calgary Zoo asked visitors to its gorilla pavilion to keep wearing masks even after Alberta’s mandate lifted, in order to protect Dossi, a pregnant gorilla. At the time, Jamie Dorgan, the Calgary Zoo’s director of animal care, health and welfare, told The Narwhal that the zoo was preparing its animals for the Zoetis vaccine to be authorized. Vaccinating wild animals is “quite a process,” said Dorgan. “A few animals have training for injections, where they’ll come over to the staff. For most, not so much.” Less willing animals are vaccinated from a distance using a dart. 

A spokesperson said it is not clear when the Calgary Zoo will be receiving vaccines. The Toronto Zoo said in a press release that it will get just over a third of the vaccines and plans to vaccinate 146 animals. Zoetis declined to say which zoos are receiving vaccines through this shipment.  

The vulnerability of animals to COVID-19 is of increasing concern to scientists in Canada and around the world. COVID-19 is in Canada’s wildlife population: in December, Environment and Climate Change Canada announced positive cases in white-tailed deer in Quebec, followed by cases confirmed in Ontario, Saskatchewan and Manitoba. Wildlife are particularly worrisome, as they can’t be isolated and are difficult to vaccinate. Culling is undesirable and also isn’t likely to be effective while COVID-19 is still circulating in humans, since deer are almost certainly getting the virus from us. 

Scientists worry about large animal populations becoming sick, though so far it seems COVID-19 is mild for most of them. They also worry about animals becoming a reservoir for the virus, in which it mutates into a variant that jumps back to humans, especially one that makes COVID-19 more dangerous. At the end of February, a team of researchers led by the Canadian Food Inspection Agency released not-yet-peer-reviewed research announcing the discovery of a new lineage of SARS-CoV-2 in Ontario deer. A lineage isn’t a variant, but it’s divergent enough to take notice of, especially since there was also possible evidence that the lineage had been transmitted from deer to a human. 

Domestic cats and dogs have also tested positive in Canada, along with farmed mink. The Canadian Food Inspection Agency is not pursuing use of the Zoetis vaccine in pets right now, but approved a course of it for emergency use in Canadian farmed mink last fall. The governments of Canada and Nova Scotia split the cost of 54,000 doses of the vaccine, which was administered on five mink farms in the province from November 2021 through January 2022. 

A spokesperson for the Nova Scotia department of agriculture said in an email that future availability of the vaccine is unknown right now. The province has not had any outbreaks on mink farms — all of Canada’s mink outbreaks were in British Columbia, which had outbreaks on three farms last year. According to CBC, the B.C. government declined to fund the vaccine for commercial mink. Instead, it has begun winding down the province’s mink industry, with plans for a complete closure by 2025.  

Lood said that no animals have been reported as having adverse reactions to the Zoetis vaccine, and complete efficacy data in different species is still being collected. 

Updated March 17, 2022 at 12:58 p.m. ET: This story has been updated to note that Zoetis is selecting which Canadian facilities will receive vaccines, and distributing them directly. A previous version of this story stated that Canada’s Accredited Zoos and Aquariums is distributing COVID-19 vaccines, and that the Calgary Zoo was not accredited by the organization. In fact, the Calgary Zoo withdrew its membership voluntarily. 

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