The drought that has plagued Brazil’s semiarid Northeast region since 2012 is already more severe than the 1979-1983 drought, the longest in the 20th century. But prolonged dry spells no longer cause the tragedies of the past.

Childhood immunisation is one of the safest and most cost-effective health interventions available, yet many of the world’s most vulnerable children continue to miss out.

A World Health Organisation report entitled State of inequality: childhood immunisation was released last week. While the report is mostly good news, immunisation rates are up and many countries have eradicated diseases entirely, a large population of children remain unimmunised.