Three cats infected with the virus that causes COVID-19 spread the virus to three other cats in a lab study published in The New England Journal of Medicine by a research team working in Tokyo, Japan, and Wisconsin, USA.

The research team emphasizes that there is no evidence of the COVID-19 virus transmitting from cats to humans. Researchers state that it is much more likely that humans are giving the virus to their pets, rather than pets causing humans to become sick. The research team infected three cats with large doses of the virus that causes COVID-19, SARS-CoV-2, directly into both eyes, both nostrils, the mouth and the trachea (windpipe). The infected cats were housed in pairs with uninfected cats, sharing the same space, food, water, and air. Within five days, the uninfected cats tested positive for SARS-CoV-2 in nasal swabs. After their first positive test, all cats continued to test positive for about five days, meaning the cats were likely infectious — able to spread the virus to others — for about five days.

Blood tests showed that the cats produced antibodies, molecules that the immune system uses to eliminate current infections, and prevent future re-infection, for 24 days after first becoming infected, the longest time included in the study.