Philly Zoo almost halfway through first batch of vaccines for animals

The Philadelphia Zoo has fully vaccinated 46 animals, from gorillas and orangutans to cheetahs and meerkats, against COVID-19 since September.

Why it matters: Wild animals can also contract the virus. Big cats and great apes seem to be most susceptible to its adverse effects, according to experts.

What's happening: The Philadelphia Zoo started vaccinating animals as a precaution this year, according to its director of animal health, Keith Hinshaw.

• Zoo officials are working to vaccinate a total of 113 animals with doses provided by Zoetis, a former subsidiary of Pfizer that develops medicine and drugs for animals.
• Thirteen animals, including the red pandas, will receive their second of the two-dose series later this week.

How it works: Zoetis handles government approvals because the two-dose vaccine is experimental.

• Each use needs to be authorized by the U.S. Department of Agriculture and the state.

Zoom out: Almost 300 animals nationwide have tested positive for the virus, according to the USDA. Routine testing of animals isn't recommended, so that figure could be higher.

• Zoos across the country have documented cases of animals getting sick from COVID-19, including lions and tigers at Smithsonian's National Zoo in Washington, D.C., and the Bronx Zoo in New York City.
• Last week, three snow leopards died of complications from the virus at Lincoln Children's Zoo in Nebraska.

Between the lines: Snow leopards in particular seem to be getting hit the worst among zoo animals, Hinshaw said.

• The Delta variant of the virus is usually the culprit.

Of note: Philadelphia's zoo hasn't had any confirmed cases of COVID-19, according to Hinshaw.

• The zoo has conducted three tests over the past 18 months.

What's next: The zoo will be asking for more vaccines in the coming months, but for less than 10 animals.

• But that could change if the zoo acquires a new animal in need or a baby is born.