Tedros Adhanom Ghebreyesus, head of the World Health Organization, has expressed concerned over the 'narrowing window of opportunity' to tackle Covid-19, and has urged the international community not to squander it. With four new cases in Iran, concern has increased about the epidemic spreading across the Middle East, and the sharp devaluation of the Iranian rial means it will be hard for its government to throw the same resources at the epidemic as China has

