It could prove necessary to vaccinate domestic animals such as cats and dogs against Covid-19 to curb the spread of the virus, scientists have suggested.
“It is not unthinkable that vaccination of some domesticated animal species might be necessary to curb the spread of the infection,” the researchers wrote in an editorial for the journal Virulence.
Last year, Denmark’s government culled millions of mink after it emerged that hundreds of Covid-19 cases in the country were linked with coronavirus variants associated with farmed mink.
Cock van Oosterhout, professor of evolutionary genetics at UEA and one author of the editorial, said dogs and cats can contract coronavirus but that there are no known cases in which there has been spillback to humans.
“It makes sense to develop vaccines for pets, for domestic animals, just as a precaution to reduce this risk,” he said. “What we need to be as a human society, we really need to be prepared for any eventuality when it comes to Covid.”
He added that the best way to do this is to consider the development of vaccines for animals as well. “Interestingly, the Russians have already started to develop a vaccine for pets, which there’s very little information about,” he continued.
Professor Kevin Tyler, editor-in-chief of Virulence, said: “Cats are asymptomatic but they are infected by it and they can infect humans with it. The risk is that, as long as there are these reservoirs, that it starts to pass, as it did in the mink, from animal to animal, and then starts to evolve animal-specific strains, but then they spill back into the human population and you end up essentially with a new virus which is related, which causes the whole thing all over again.”
He said that while mink were culled in Denmark, “if you were thinking about domestic animals, companion animals, then you might think about whether you could vaccinate to stop that from happening”.
He added: “It’s not an obvious risk yet.”
Prof van Oosterhout and Prof Tyler wrote the editorial along with the director of the Earlham Institute, Neil Hall, and Hinh Ly of the University of Minnesota.
In their editorial, the scientists wrote: “Continued virus evolution in reservoir animal hosts, followed by spillback events into susceptible human hosts, poses a significant long-term risk to public health.
“SARS-CoV-2 can infect a wide range of host species, including cats, dogs, mink and other wild and domesticated species and, hence, the vaccination of domesticated animals might be required to halt further virus evolution and spillback events.
“Whilst the vaccination campaigns against Sars-CoV-2/Covid-19 are being rolled out worldwide, new virus variants are likely to continue to evolve that have the potential to sweep through the human population.”
They said that more transmissible virus strains, such as the UK variant, require more people to be vaccinated to keep coronavirus under control. “Vaccination against a viral pathogen with such high prevalence globally is without precedent and we, therefore, have found ourselves in uncharted waters,” they wrote.
The scientists have called on governments to consider the continued use of strict control measures, such as masks and social distancing, as the only way to reduce the evolution and spread of new Covid-19 variants.