Farmed mink are highly susceptible to SARS-CoV-2 infection and, in some cases, they have transmitted the virus back to humans. Surveillance findings in Denmark and the Netherlands show that SARS-CoV-2 introduced into mink populations continues to evolve through viral mutation. Viral mutation also happens in human infections, but new mutations may be seen as the virus adapts to a new species. Scientific investigations have confirmed that SARS-CoV-2 infection has been reintroduced from mink to humans. WOAH acknowledges that such events could have important public health implications. There are concerns that the introduction and circulation of new virus strains in humans could result in modifications of transmissibility or virulence and in decreased treatment and vaccine efficacy. Yet, the full consequences remain unknown, and further investigation is needed to fully understand the impact of these mutations. Read more in WOAH's Statement on COVID-19 and mink.