Gorillas, otters, yes-yes and many more will soon join the ranks of those vaccinated against COVID-19.
The Philadelphia Zoo is preparing to vaccinate its most-at-risk animals with an experimental vaccine developed by Zoetis, a former Pfizer subsidiary that develops medicine for animals. Although animals are not a major concern for the spread of the virus to humans, according to the Centers for Disease Control and Prevention, they can still be infected. Cases have been reported in some big cats and gorillas in zoos, domestic animals and farmed mink, prompting zoos across the country to help their animals strengthen their immune defenses.
“We were concerned that the animals were susceptible and we started taking precautions pretty early on,” said Keith Hinshaw, director of animal health at the Philadelphia Zoo, who is awaiting state approval before proceeding. “This vaccine is really what we have been looking for from the start. “
Zoo precautions included face shields and gloves for zookeepers and minimizing the time they spent within six feet of animals – which was not always easy for animals used to interacting with their companions. humans. “When the state was on lockdown, I would walk around the zoo and the animals would be very excited to see a person,” Hinshaw said.
But there were good reasons to be careful. The gorillas at San Diego Zoo Safari Park not only became infected with COVID-19, but also developed unpleasant symptoms like cough and congestion, which alarmed Hinshaw. When he heard about an experimental vaccine from Zoetis that the San Diego Zoo had administered to their great apes, he immediately contacted the New Jersey-based company to see how the Philadelphia Zoo could stock up on supplies.
Zoetis originally thought there might be demand for a COVID-19 dog or cat vaccine, but switched to mink when outbreaks on farms prompted the US Department of Agriculture to call for COVID-19 vaccines for mink. Now this vaccine, still in development, is being distributed to zoo animals.
“We can’t make a new vaccine for every species,” said Mahesh Kumar, senior vice president of global biologics at Zoetis. But the company believed its prototype, which appeared to be safe and effective for cats, dogs, and other species, could work for a larger menagerie.
Zoetis is donating over 11,000 doses to over 70 zoos and other animal organizations that will be administered to everything from meerkats to orangutans. To maximize effectiveness, Zoetis asks zoos to administer two doses: the first to prime the immune system, then a second to stimulate the response weeks later, like human vaccines. “Even in a large animal, you will get some level of protection,” Kumar said.
The animal vaccine is not quite the same as the vaccines that humans receive. Both are designed to teach the immune system to recognize the spike protein that gives the coronavirus its characteristic crown-shaped halo. This way, if the immune system encounters the protein again – due to an infection – it knows how to defend the body. But unlike human COVID-19 vaccines which use RNA to provide genetic instructions to make the spike protein, the Zoetis vaccine provides chunks of the spike protein made in the lab. Regardless of the species infected, it is impossible to contract the disease from the vaccine because it does not deliver all of the functional virus.
The Zoetis vaccine also uses an adjuvant – a material supplied with the spike protein to attract the attention of the immune system – designed for cats and dogs that appears to work in other animals as well.
Zoetis does not yet know how all species will respond to the vaccine, but zoos will be encouraged to share any adverse events that occur. Some zoos have been wary and a study is underway to measure efficacy and safety, said Michele Goodman, director of veterinary services at Elmwood Park Zoo in Montgomery County. The Elmwood Park Zoo has not decided whether to participate.
Hinshaw knows that giving an investigational vaccine can come with risks, but feels more comfortable because the vaccine does not contain live virus and because it has already been given safely by others. zoos. The benefits are substantial, he said: keeping the animals and zoo staff healthy, and minimizing the opportunities for the virus to replicate and pick up mutations that make it more contagious, like the delta variant which is now causing an increase in cases in the country and around the world. unvaccinated people.
“It’s a bit of extra reassurance that we’re trying to do our best to take care of the animals,” Hinshaw said.
As with the deployment of the human vaccine, in which certain groups have been prioritized, certain animals will have to wait their turn. Primates top the list, starting with great apes such as gorillas and orangutans, as their biological similarity to humans could make their cells an easier target for the virus. The rest of the monkeys will follow, including the gibbons and mangabeys. About 40 carnivores should also be vaccinated, starting with the big cats – lions and tigers – as well as otters, bears, etc.
Many animals are seasoned vaccines and have already been trained to cooperate with routine rabies and distemper vaccines, Hinshaw said. Tigers, for example, will walk to the front of their enclosure, turn onto their side, lie down, and rest their shoulder or thigh against a mesh panel. There is of course a treat in play: a keeper stands by with pieces of meat or a bottle of milk as a reward.
The Philadelphia Zoo is waiting for the state to approve the use of the vaccine before it can receive and administer the doses, but Hinshaw expects that to happen within the next two months.
COVID-19 pet vaccines have yet to be approved by regulatory bodies, so don’t even try to call your vet. For now, Kumar has some simple tips for concerned pet owners: “The best thing you can do is get vaccinated.