Via ReliefWeb, an OCHA report: El Niño: Snapshot of Impact and Projected Humanitarian Needs as of 22 December 2015. Click or tap through to download the PDF. Excerpt from the summary:
In 2016, an estimated 22 million people may suffer from food insecurity in Eastern Africa, and 4.7 million people in the South Pacific may be at risk from adverse weather associated with El Niño. In Southern Africa, where 30 million people are already food insecure after a ruinous 2015, the situation will only worsen throughout 2016 due to El Niño and relief might only come with the 2017 harvest.
People most vulnerable, including children, the elderly and women, are at greatest risk. Currently, over half a billion children are living in areas with extremely high levels of flood occurrence, and nearly 160 million people live in areas of high or extremely high drought severity. Children are also far more vulnerable to disease than adults.
Excessive rainfall could trigger and exacerbate outbreaks of waterborne diseases such as cholera and typhoid as well as vector-borne diseases such as malaria, which will affect millions of people. There could also be an increased impact on livestock such as through Rift Valley Fever outbreaks can also infect humans. In the 1997-98 El Niño event, unprecedented outbreaks of Rift Valley Fever occurred in Kenya, Somalia and Tanzania, with nearly 90,000 people infected and 500 deaths.
Although the climate impacts of El Niño on seasonal rainfall are expected to end before mid-2016, the health effects are likely to continue until the third quarter of 2016 or to the new harvest season