A senior US aid official has warned that the next health crisis facing Syrian children may be measles, as the Syrian government refuses to implement a UN Security Council resolution demanding urgent improvement in humanitarian access to war-battered populations.

In a March 31 interview with Al-Monitor, Nancy Lindborg, assistant administrator for the Bureau for Democracy, Conflict and Humanitarian Assistance at the US Agency for International Development (USAID), said that the World Health Organization (WHO) and UNICEF have managed to make progress against an outbreak of polio in Syria, but added, “What we are seeing with the coming of warm weather is the possibility of measles outbreaks.”

While the polio vaccine can be relatively easily transported and administered orally, the measles vaccine must remain chilled and be administered by injection, making it even harder for aid workers to reach vulnerable populations. The threat has grown because of the collapse of the Syrian public health system over the past three years of war and, increasingly, the lack of food.

“We’re starting to see real malnutrition in the under-5 population,” said Lindborg, further explaining that malnutrition weakens resistance to infectious diseases. “WHO and UNICEF have been very heroic, with more success than anticipated on polio. The measles piece will be much more challenging.”