A first-of-its-kind trial has been launched to test a new vaccine for bird flu in humans. Thousands of people in the UK are expected to be recruited for the study, with poultry farmers or those who have close contacts with birds encouraged to sign up. The A(H5N1) strain of the virus is “evolving and spreading” in animals, and while it does not yet move easily between people, human-to-human transmission must be treated “as a real possibility”, experts said. The mRNA-1018 vaccine, developed by