How can vaccinating pigs protect people?

Many disease outbreaks, including Covid-19, are caused by viruses that have jumped from animals to humans. At the Pirbright Institute in the UK, Dr Rebecca McLean and Professor Simon Graham are studying one particular virus which did this in 1998 and continues to pose a threat today. They have developed and tested potential vaccines which, if delivered to pigs, could prevent future outbreaks of Nipah virus in humans.