When it's time to be vaccinated, the apes at the San Diego Zoo and its associated safari park sit still and allow veterinarians to inject their arms through a barrier.
"It's pretty amazing," said San Diego Zoo Safari Park director Lisa Peterson. "Our great apes are trained to participate in their own care."
On Jan. 11, a troop of eight gorillas at the safari park tested positive for the coronavirus. They were quarantined, received treatment, and are now recovering.
"We're seeing their everyday personalities and vivaciousness coming back, so we're very excited that we were able to get them through it," said Peterson.
But after the outbreak among the gorillas at the safari park, both the park and the zoo decided to vaccinate other apes. Six bonobos and four orangutans at the zoo and three gorillas at the park have since gotten shots. Among them was Karen, the first orangutan to have open heart surgery back in 1994.
As the pace of COVID-19 vaccinations speeds up across the country, zoos across the country are considering whether to give shots to apes and other animals that may be susceptible to the virus.
The COVID-19 vaccine that the San Diego Zoo used on its apes was produced by the veterinary pharmaceutical company Zoetis. The U.S. Department of Agriculture says it approved the vaccine for experimental use by the zoo.
It is not the same vaccine as any of the ones being given to humans. Mahesh Kumar, senior vice president of global biologics at Zoetis, says that although the virus is the same, the adjuvant — an ingredient in the vaccine that helps boost immune response — has to be different.
"The carrier or the adjuvant that's mixed with this antigen needs to be specific to the species," he says.
Zoetis started developing a COVID-19 vaccine for dogs and cats last year, when they saw that dogs in Hong Kong were getting infected. However, the U.S.D.A has not approved vaccines for dogs and cats, though they are considering a vaccine for minks, which are highly susceptible and had to be culled in Denmark after a massive outbreak last year.
Kumar says that many other zoos have contacted Zoetis about its vaccine.
But some zoos are more focused on vaccinating staff who work with animals first. The Saint Louis Zoo is one of them.
"The biggest thing we do to keep our animals safe is to keep our staff safe," said Dr. Luis Padilla, a veterinarian and the vice president of animal collections at the zoo.
He said staff at the zoo wear PPE around the animals and undergo daily screenings for COVID-19 symptoms and exposures. The San Diego Zoo and Safari Park have also vaccinated their staff.
Zoos are also monitoring their animals to see if any new knowledge can be gained into how viruses get transmitted between animals and humans.
According to the Centers for Disease Control and Prevention, 75% of emerging infectious diseases come from animals. COVID-19 is thought to have originated in bats and passed to humans in 2019.
Learning more about cross-species transmission could prevent future pandemics, says Dr. Sharon Deem, an epidemiologist at the Saint Louis Zoo.
"So a few years from now, you don't call us and ask about COVID-23 or COVID-25," she says, using the naming convention that incorporates the year of transmission.
Zoos are one of the few controlled environments where humans and wildlife interact. And both vaccinating animals and protecting zoo staff are rooted in the notion that the health of animals and humans are interconnected, an idea known in public health circles as One Health.
"We have to care for the plants and the animals and the habitats and environments in which they live if we want to protect ourselves," said Peterson of the San Diego Zoo Safari Park.