The hantavirus outbreak has been well-handled – but there are still dangerous days ahead | Devi Sridhar

Hantavirus: the disease you wish you’d never heard about, as visions of the Covid pandemic race through your head. I’ve seen a lot of jaw-dropping reports and bizarre takes on social media, so I imagine a lot of people are confused as to what’s going on.

Let me start by saying that this is not about the Covid pandemic – only Covid was Covid. Previous hantavirus outbreaks have been contained (although none occurred on a cruise ship). So, for now, the risk to the general public is low – my colleagues and I are continuing our activities as normal and monitoring if any new infections arise outside of the original cruise ship group. These new infections would be a key milestone determining whether we see further spread and higher-risk public health alerts – or whether we are at the end of this epidemic.

The first thing to know is that cases of hantavirus occur regularly all over the world. You just don’t hear about it. In fact, you probably haven’t heard about the 2018 Andean-strain hantavirus outbreak in Argentina, with 34 confirmed cases and 11 deaths.

Part of what makes the current outbreak unique — and newsworthy — is that it’s on a cruise ship with about 150 people of 23 nationalities. Cruise ships are notorious for making outbreaks difficult to control, given the close living conditions, frequent stopovers at various ports, the nature of passengers traveling around the world, and the difficulty of managing a public health response on board the ship once a virus is detected.

Do you keep everyone on the ship, lest other people become infected and sick? Or do you take people off the ship and risk it spreading to each of their countries of origin? In this case, a number of passengers disembarked before the outbreak was detected and took commercial flights home, meaning there is already wider potential exposure to the virus. We will only know for sure in the coming weeks.

When hantavirus was first mentioned, public health experts hoped it was a strain other than the Andean strain, which can be transmitted from human to human and has already caused superspreading events. Add to that the fact that it has an incubation period of one to eight weeks, meaning just because someone tests negative today doesn’t mean they aren’t infected. They could still become symptomatic and contagious later.

We also do not have an approved vaccine, specific therapeutic test, or rapid diagnostic test that could be deployed against this strain. This means having to rely on the traditional public health measures of isolation and quarantine, N95 masks, and stopping chains of infection.

We’ll know how many other people were infected on the cruise ship in a few days, so expect more positive cases. We will also know within a few weeks whether secondary contacts on flights and elsewhere were infected by passengers who disembarked before the outbreak was identified. None have been identified so far, which is good news. But it’s also the beginning.

And it is imperative that those returning to their home countries have logistical, medical and emotional support to quarantine for the full WHO-recommended 42 days and not infect close contacts, such as family and friends, that they may want to see. Given the long incubation period, this could mean cases appearing in one to two months and more infection chains closing. We are also in a unique situation where we rely on 23 different governments to successfully manage the return of their nationals.

Finally, all of this has been made more difficult by the fact that the United States has historically been the leader in investigating and responding to outbreaks through the Centers for Disease Control and Prevention (CDC). But he recently left the World Health Organization (WHO) and fired all of the CDC’s cruise inspectors. It must be recognized that WHO took the lead in the response, working with ship personnel and multiple governments to coordinate a coherent and integrated response. All of these different countries are welcoming back their nationals and should all follow a similar containment protocol.

Here, the UK Health Security Agency (led by Professor Susan Hopkins) has played a leading role in this – and to its credit has adopted a sensible, scientific and proactive response in managing the outbreak. For example, using self-contained apartments at Arrowe Park Hospital in Wirral, Merseyside, to house everyone who comes off the ship and ensuring they have a supported isolation arrangement with regular medical tests and assessments. They also handled Kent’s meningitis outbreak well.

Even as new cases arise, scientists are already looking for solutions: vaccine studies are being accelerated, existing drugs that may work against hantavirus are being studied, and diagnostics are being tested. We hope that knowing that some of the world’s brightest minds are researching solutions will help you sleep better at night, too.

• Professor Devi Sridhar is Chair of Global Public Health at the University of Edinburgh and author of How Not to Die (Too Soon)