polio

A health worker administers a polio vaccine to a child, in Enjil district of Herat, Afghanistan, 11 May 2015. Pakistan, Nigeria and Afghanistan are considered to be the only countries where the poliovirus is still endemic.

Jalil Rezayee/EPA

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

An Afghan health worker administers polio vaccine drops to a child on the second day of a vaccination campaign in Kabul on March 16, 2015. Nearly nine million children throughout Afghanistan will be immunized during a three-day national polio immunization drive launched on March 15.The immunization campaign comes shortly after Afghanistan reported its first case of polio virus for 2015, in Helmand, in the Southern Region. Afghanistan and Pakistan are the only two countries in the world to have reported cases of the crippling polio virus in the past eight months and it is increasingly likely that these are the last two countries on Earth with active polio transmission

Shah Marai/AFP

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

Parwiz/Reuters

A girl receives polio vaccination during an anti-polio campaign on the outskirts of Jalalabad on Monday

Pakistani girls show their fingers being marked after receiving polio vaccine in Lahore, Pakistan, Tuesday, June 3, 2014. Pakistan required  all travelers leaving the country to obtain a polio vaccination, the health ministry said

K.M. Chaudary/AP

Girls show off their painted fingers after receiving the polio vaccine in Lahore, Pakistan, on Tuesday

Pakistani health workers mark the thumb of a child after giving him polio vaccine drops to a child during a polio vaccination campaign in Rawalpindi, Pakistan, on February 25, 2014. Pakistani health workers go door-to-door to administer vaccinations to children for various diseases including polio, tuberculosis, tetanus, whooping cough, measles and hepatitis.Dr. Elias Durry, coordinating the World Health Organizations support to Pakistans polio eradication effort, said recorded 70 cases of polio last year and vaccinated 34 million children.

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 Pakistani woman walks out of her home carrying her child towards a health worker to be vaccinated against polio in Islamabad, Pakistan, Monday, Nov. 25, 2013. On Saturday, militants kidnapped four school teachers who were working on a polio vaccination drive in Khyber's Sipah village, said local government official Khurshid Khan. Negotiations are underway for their release, he said. Militants have killed over a dozen polio workers and police protecting them over the last year and they claim the workers are spies and the vaccination is meant to make Muslim children sterile.

Muhammed Muheisen/AP

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.

An Afghan health worker (2R) administers a polio vaccination to a child on the first day of a vaccination campaign in Herat. A new three-day nationwide immunisation campaign against polio began supported by Afghanistan's Ministry of Public Health country wide, officials said.

Aref Karimi/AFP

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

Pakistani health worker Salma Saleem, right, marks the finger of a child after giving him a polio vaccine

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.