Arhab is five years old, which makes him the same age as the conflict in Yemen. Last month he and his family walked for three days through the country’s northern deserts to escape shelling and aerial bombardment. That was the second time in his short life he has been forced to flee. 

As the war in Yemen enters its sixth year, 80 percent of the population, or 24 million people, depend on humanitarian aid for their survival. Since arriving in Sana’a to lead the UNHCR team here, I have seen up close the malnourished children and health centres destroyed by the fighting that I had previously only glimpsed in the media. Food shortages and diseases such as cholera are constant companions of this conflict.

Now Yemen, in common with countries across the globe, faces the threat of the coronavirus. It is a threat made significantly worse for those, like Arhab, who live in one of the 1,700 overcrowded sites where displaced families have found temporary safety – conditions that render concepts such as social distancing meaningless. 

For three years running, the UN has called what has unfolded in Yemen the world’s worst humanitarian crisis. Arhab is one of almost four million people displaced by a war deepened and fueled by competing regional powers.  

As the leading UN agency responsible for protecting people forced to flee, UNHCR is assisting not only those within Yemen who have been driven from their homes, but also 280,000 refugees, mainly from Somalia. The latter have made one of the most dangerous crossings anywhere in the world – but as they are denied safe pathways to more stable regions, many feel they have little to lose.   

Mounting a coronavirus prevention and response programme in such circumstances is a daunting challenge.   

Half of the country’s health facilities have been destroyed by the violence. The rainy season will bring flooding that will destroy improvised shelters and threaten another bout of cholera. New fighting is displacing yet more people: in Marib governorate, where Arhab now lives, thousands of families face food and water shortages. Handwashing is one of the main defences against Covid-19 but water in Yemen is scarce: among displaced communities it is common for 50 families to share one toilet.  

Reaching those who most need our aid is not easy. There are vulnerable people located close to the front lines of the war, making our Covid-19 work even harder. A ceasefire is needed, and now. But if the choice is between staying and helping as many people as we can or turning our backs when they need us the most, there is no doubt where our obligations lie.  

Through cash payments, we help displaced families pay rent or build their own shelters. We ensure births are recorded so that children can register in school and get access to medical treatment.  

These days, we are distributing hygiene kits and raising awareness about coronavirus transmission. And we do what public health authorities elsewhere are doing by establishing protocols for community leaders to deal, in a humane and dignified manner, with suspected cases. 

But we could do more. This year we have received only 28 per cent of the $212 million required. We have the experience and expertise to assist displaced Yemenis and refugees – including protecting them from the coronavirus – but without the means to do so we are severely constrained. The consequences of leaving so many vulnerable people at the virus’s mercy after five years of war, without basic sanitation and proper health facilities, are likely to be devastating.  

Our donors are preoccupied – and rightly so – with their domestic public health priorities and the serious economic challenges that follow. But as the world fights Covid-19 with all the means at its disposal, the question is whether we turn our backs on those least equipped to fight the virus, or whether global humanitarian solidarity prevails.  

There is little standing between millions of people like Arhab and catastrophe. Antonio Guterres, UN Secretary-General, has said the world is only as strong as its weakest health system. Right now, that weak point is Yemen.