A soldier guards polio vaccination team administering polio vaccination to children during a three-day countrywide vaccination campaign in Peshawar, Pakistan. Though new polio cases dropped to a nine-year low in 2016, attacks by Islamist militants against health workers and police guarding them remained a challenge for a UN-funded vaccination campaign. Photo Arshad Arbab/EPA
An Afghan girl looks on as a health worker administers polio vaccine drops to others during a vaccination campaign on the outskirts of Jalalabad. Polio, once a worldwide scourge, is endemic in just three countries now – Afghanistan, Nigeria and Pakistan. Photo Noorullah Shirzada/AFP/Getty
Police guard a polio vaccination team, during a three-day vaccination campaign in Karachi. Pakistan. Though new polio cases dropped to a nine-year low in 2015, attacks by Islamist militants against health workers and police guarding them remained a challenge for a UN-funded vaccination campaign.
AP Photo/Allauddin Khan
An Afghan burqa clad female health worker gives a vaccination to a child during a polio campaign in Kandahar, Afghanistan, on Monday
A Pakistani health worker administers polio drops to a young girl during a polio vaccination campaign in Karachi on Monday
A girl receives polio vaccine drops during a house-to-house vaccination campaign in Yemen’s capital Sanaa on Tuesday
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 health worker administers a polio vaccine to a child, in Enjil district of Herat, Afghanistan on Monday. Pakistan, Nigeria and Afghanistan are considered to be the only countries where the poliovirus is still endemic
A health worker gives polio vaccine drops to a child on the second day of a national campaign in Afghanistan on Monday. Nearly nine million children in the country are being immunised during the three-day programme.
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.
A health worker administers a polio vaccination to a child in Herat, Afghanistan, at the start of a three-day nationwide immunisation campaign against polio, supported by the country’s Ministry of Public Health
Muhammed Muheisen/AP Photo
Pakistani health worker Salma Saleem, right, marks the finger of a child after giving him a polio vaccine in a neighborhood in Islamabad, Pakistan on April 15 2013. In December, gunmen killed nine polio workers in different parts of Pakistan. Several more workers have been killed since then, as well as policemen who were protecting them. The UN said last month that some 240,000 children missed vaccinations since July in parts of Pakistan’s tribal region, the main sanctuary for Islamic militants, because of security concerns.