What is Nipah virus, the 'high priority pathogen' with up to 75% fatality rate? ‌The UK Health Security Agency (UKHSA) has designated Nipah a "high priority pathogen" due to its high fatality rate and lack of proven treatment for the virus, which carries a fatality rate of up to 75%. ‌The UKHSA warned between 40% and 75% of those infected with the Nipah virus will die. Person to person spread is possible should they be in close proximity with an infected person or their body fluids. Unfortunately, there is no proven specific treatment for Nipah virus infection, and no preventative vaccine is licensed to use.