ONEIn early 2021, four orangutans and five bonobos became the first great apes in a United States zoo to receive the Covid-19 vaccines. An outbreak in the western lowland gorilla troop at the San Diego Zoo caused panic among employees after the virus spread to the animals, probably from an asymptomatic handler. Eight gorillas tested positive – with symptoms such as runny nose, lethargy and cough – and there were fears that the virus could spread to other primates.
“We were approached by the San Diego Zoo asking if we had a vaccine because the primates were getting sick. Fortunately, we had some that we considered appropriate, ”recalls Dr. Mahesh Kumar, senior vice president of the US veterinary pharmaceutical company Zoetis, who developed the jab.
The great apes of California have fully recovered, but since the beginning of the pandemic, we fear for the welfare of our closest cousins. In March 2020, experts warned that this could wipe out populations of chimpanzees, gorillas and orangutans because of their genetic proximity to humans. National parks in the Democratic Republic of Congo and Rwanda quickly closed their doors to tourists as a precautionary measure, and many forest rangers now adhere to strict guidelines for social distance from animals. So far, the warnings have not come true, but the virus has spread rapidly to other groups of animals.
The Zoetis vaccine that the great apes received at the San Diego Zoo in January and February is being developed especially for mink, after outbreaks on dozens of farms around the world. Sars-CoV-2 is highly transmissible among animals and has high morbidity and mortality. Another American company and researchers in Russia are also developing mink vaccines, according to the New York Times.
Millions of carnivorous mammals have been slaughtered as a precaution in Denmark, the world’s largest exporter of mink fur, with corpses buried in shallow pits. Genetic analysis of Danish strains in cultivated mink found that the mutations were unlikely to harm human vaccines and therapies, but several scientists supported the controversial selection to prevent uncontrolled spread among mink populations. Thousands of mink died after catching the virus and it was detected in wild animals during animal surveillance near a mink farm in Utah.
If approved for use in mink by US regulators, Kumar believes the vaccine can also benefit humans, potentially stopping the emergence of new variants of the coronavirus that can undermine human immunization efforts. The company needs to show regulators that the vaccine has a reasonable expectation of efficacy and safety and is conducting tests with mink breeders in the United States. To date, there is no blood test data on the vaccine’s effectiveness in large monkeys, but it found a strong immune response in the mink.
“We clearly know that mink in Denmark was able to transmit the virus back to humans. The mink contributed some changes to the virus, so we are obviously concerned about the repercussions of the mink back to humans. So by protecting the mink, it prevents the virus from spreading back to the human population, ”says Kumar.
“We make and develop vaccines for several species, including coronavirus vaccines. So, we have used the knowledge to develop this [for Covid-19]. We had several formulations that we tested on dogs and cats when we were contacted by the San Diego Zoo. “
Kumar says Zoetis received several requests from other US zoos to use the experimental jab – similar to the Novartis vaccine for humans – after vaccination against great apes made headlines around the world. But each injection requires emergency authorization from the United States Department of Agriculture (USDA) and there are strict rules on the commercial use of the vaccine, with developers authorized to sell inoculations only for the declared species.
Zoetis, which left Pfizer in 2013, started developing the vaccine after family pets in Hong Kong began testing positive for Covid-19, fearing that dogs and cats could be vectors of spread from animal to human . There is no evidence that this is the case, but in the UK Veterinarians have warned of a possible link between the coronavirus strain Kent and heart problems in dogs and cats.
In the USDA notice announcing it would accept licensing applications for vaccination of mink vaccines against Sars-CoV-2, the agency said there was very limited evidence that the disease has spread among dogs and cats in non-laboratory settings. He concluded that a Covid-19 vaccine for pets would be of no value and would not grant licenses for species other than mink without further evidence of transmission. Kumar says Zoetis is ready if the virus changes.
“Obviously, we don’t want this to go into cats and dogs. However, for us, it is a significant concern that if the virus changes and mutates in a way that becomes more infectious in dogs and cats, we will be ready. We are quite confident that we will have something very quickly if something like this happens. “