A health worker administers a polio vaccine to a child, in Peshawar, Pakistan on Monday. Pakistan still accounts for the majority of polio cases globally
A girl receives polio vaccination during an anti-polio campaign on the outskirts of Jalalabad on Monday
Girls show off their painted fingers after receiving the polio vaccine in Lahore, Pakistan, on Tuesday
Metin Aktas/Anadolu Agency/Getty Images
Pakistani health workers mark the thumb of a child after giving him vaccine during a polio vaccination campaign in Rawalpindi, Pakistan. Pakistani health workers go door to door to administer vaccinations to children for diseases including polio, tuberculosis, tetanus, whooping cough, measles and hepatitis.
A woman in Islamabad, Pakistan, takes her child to a health worker to be vaccinated against polio. More than a dozen polio vaccine workers have been killed by militants in the past year in the country. They claim the workers are spies and the vaccination is intended to make Muslim children sterile.