The Himalayan nation has experienced intermittent success with its oral vaccine-focused campaign, as new cases have turned up every few years, most recently in 2010, when the outbreak was blamed on cross-border transmissions from neighbouring India.
Since the oral vaccine contains a weakened form of the live polio virus that can cause infections, experts have called for it to be supplemented and eventually replaced with the injection, which is already used in dozens of developed countries.
"The last transmission of polio from one person to another in Nepal was almost five years ago," Nepalese Health Minister Khaga Raj Adhikari said at the launch.
"Today, we start to make sure that not one of our children will ever again have her future stolen or his dreams destroyed by this disease."
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The polio virus spreads through faecal matter, attacks the central nervous system and can leave its young victims crippled, paralysed or dead.
Bangladesh was one of 11 countries to be certified as polio-free by the WHO last March after going three years without reporting a new case.
Today the polio virus is considered endemic in only three countries -- Afghanistan, Nigeria and Pakistan, where the vaccination campaign has been attacked by Islamists.