FILE - A police officer escorts health workers arriving to administer polio vaccine in a slum area of Peshawar, Pakistan, Jan. 24, 2022. Aidan O'Leary, director of the World Health Organization's polio department, described the recent discovery of polio spreading in London and New York as "a major surprise," saying that officials have been focused on eradicating the disease in Afghanistan and Pakistan, where health workers have been killed for immunizing children and where conflict has made access to some areas impossible. (AP Photo/Muhammad Sajjad, File)