AAt the beginning of 2021, four orangutans and five bonobos became the first great apes in an American zoo to receive Covid-19 vaccinations. An outbreak in the western lowland gorilla herd in San Diego caused panic among staff after the virus spread to the animals, likely from a symptomatic zoo. Eight gorillas were tested positive – with symptoms such as runny nose, lethargy and cough – and it was feared that the virus could spread to other primates.
‘We were approached by the San Diego Zoo to ask if we had any vaccine because the primates were getting sick. Fortunately, we had a few that we thought would be suitable, ‘recalls dr. Mahesh Kumar, a senior vice president at the American veterinary pharmaceutical company Zoetis, who developed the jab.
The great apes in California have fully recovered, but since the beginning of the pandemic, there have been fears for the well-being of our closest cousins. In March 2020, experts warned that it could wipe out populations of chimpanzees, gorillas and orangutans due to their genetic proximity to humans. National parks in the Democratic Republic of Congo and Rwanda have quickly closed their doors to tourists as a precautionary measure, and many rangers now follow strict guidelines around social animals. So far, the warnings have not materialized, but the virus has spread rapidly through other animal groups.
The Zoetis vaccine, which the great apes received at the San Diego Zoo in January and February, is being developed especially for mink, following outbreaks on dozens of farms around the world. Sars-CoV-2 is highly transmissible among animals and has high diseases and mortality. Another U.S. firm and researchers in Russia are also developing vaccines for mink, according to the New York Times.
Millions of carnivorous mammals have been culled as a precautionary measure in Denmark, the world’s largest exporter of mink fur, with corpses buried in shallow graves. Genetic analysis of the Danish strains in the cultivated mink has found that the mutations are unlikely to undermine the vaccines and therapeutic agents for humans, but several scientists support the controversial thinning to stop the uncontrolled spread by mink populations. Thousands of mink died after catching the virus and it was detected in wild mink while monitoring animals near a mink farm in Utah.
If approved for use on mink by U.S. regulators, Kumar believes the vaccine could also benefit humans, potentially stopping the emergence of new coronavirus variants that could undermine immunization efforts in humans. The company needs to show regulators that the vaccine has a reasonable expectation of efficacy and safety, and that it is conducting trials with mink farmers in the US. To date, it has no blood analysis data on the efficacy of the vaccine in great apes, but has found a strong immune response in mink.
‘We clearly know that mink in Denmark could transmit the virus to humans. The mink has contributed some changes to the virus, so we are naturally concerned about the spread of the mink to humans. By protecting the mink, it therefore prevents the flood from returning to the human population, ‘says Kumar.
“We make and develop vaccines for various species, including coronavirus vaccines. So we used knowledge to develop it [for Covid-19]. We had several formulations that we tested on cats and dogs when we were contacted by the San Diego Zoo. ”
Kumar says Zoetis has received several inquiries from other U.S. zoos to use the experimental sting – similar to the Novartis vaccine for humans – after the big monkey vaccinations made headlines worldwide. But each sample requires emergency permission from the U.S. Department of Agriculture (USDA) and there are strict rules about the commercial use of the vaccine, and developers may only sell vaccines for said species.
Zoetis, which was rolled out of Pfizer in 2013, only started developing the vaccine after family animals in Hong Kong began testing positive for Covid-19, fearing that dogs and cats could be vectors for spreading animals to humans. There is no evidence that this is the case, but in the UK veterinarians have warned of a possible link between the Kent coronavirus strain and heart problems in cats and dogs.
In the USDA notice announcing that it will accept license applications for mink vaccinations against Sars-CoV-2, the agency said there is very limited evidence that the disease is spread between cats and dogs in non-laboratories. The conclusion was that a Covid-19 vaccine for pets would have no value and that it would not grant any licenses for species other than mink without further evidence of transmission. Kumar says Zoetis is ready if the virus changes.
‘Obviously we do not want it to end up in cats and dogs. For us, however, it is a major concern that if we were to change and mutate the virus so that it becomes more contagious in cats and dogs, we are ready. We are pretty confident that we would have something very quickly if something like this happened. ”