The UN says it may shelve plans to ship one million doses of the cholera vaccine to Yemen due to security and logistical challenges. 

The world's worst cholera outbreak in Yemen has killed tens of thousands of people in the country, many of them children. War has crippled Yemen's health system, and the country is in dire need of clean water.

"The diarrhea disease outbreak in Yemen is taking a heavy toll on the lives of common Yemenis. As of today we have 317,000 reported cases of diarrhea, along with 17,050 recorded deaths. Almost half of the cases are children. Humanitarian agencies are working round the clock to reach every corner of the country with essential health supplies as well as safe water,” said Sherin Varkey, the UNICEF Deputy Representative in Yemen.