90-Second Read: Right now, we could be living through a Hantavirus disaster. The world avoided that, and this is why

There were 147 passengers and crew, and on 4 May seven cases of respiratory illness on board were identified as the Andes strain of Hantavirus, which has been known to spread from human to human. Without rapid recognition of Hantavirus and intervention, the passengers could have been free to disembark, disperse and go back to mixing in cities and countries across the world. As of today, the Hantavirus outbreak seems to have been contained, with a total of only 13 cases, all in passengers who travelled onboard the ship. This was already an extremely unlucky outcome, Hantavirus is deadly, with death rates approaching 30% based on recent research, but most strains only spread from animals to humans.

Individual cases become clusters that start to emerge across the world as passengers are repatriated to their home countries. We also got lucky that Hantavirus isn't more contagious: we haven't seen any cases from those exposed on flights or airports before the outbreak was identified, which we might have done with a more infectious virus. It also means being better prepared next time, as 21 countries have now signed up to a coordinated Hantavirus research programme based on studying those exposed on the ship. We heard so much about what went wrong during Covid and the various systems that failed, so it's good to recognise when things go right, even if you won't hear about it in the evening news.

This is a public health success story worth celebrating, because so many worse results were possible. They pass through airports, public transport, family gatherings and supermarkets. Given the limited medical treatments, there are no approved therapeutic treatments or vaccines, governments are forced to consider various public health mandates to stop the spread, while the public are confused and scared. The coordination function of the WHO was especially important because while countries might have their own public health agencies, healthcare systems and political orientations, they had to act together to stop a worldwide outbreak.

Alongside the Spanish government, the WHO issued technical guidance to the 23 countries with passengers on the ship, setting out standardised protocols for isolation, monitoring and clinical management. In this instance, success means containment, thanks to good leadership, rapid response and worldwide cooperation. The chase to break transmission lines and identify contacts gets harder and harder as each day passes and the outbreak travels further from the ship.