90-Second Read: WHO Updates Hantavirus Advice, Stressing There’s No Reason To Expect A Pandemic

As another person is placed on a ventilator, the World Health Organization (WHO) is trying to strike the right balance in preventing complacency about the Hantavirus outbreak on the cruise ship MV Hondius without adding fuel to fear-mongering about a COVID-19-like pandemic. We would expect more cases because, as you may remember, the index case, the first case in the ship, was on 6 April … [and] there was a lot of interaction, actually, with the passengers. The reason human Hantavirus cases are rare is that most forms of the disease don't spread from human to human, only from rat to human through droppings, saliva or urine. The MV Hondius, onboard which an outbreak of Andean Hantavirus began on April 6, docked at Tenerife in the Canary Islands on Sunday 10 May, against the objections of the local government.

The WHO is recommending all passengers from the ship be placed in 42-day quarantine, reflecting the virus's long incubation period. Fortunately, current evidence suggests that, unlike for COVID-19, people with Hantaviruses aren't infectious before they show symptoms themselves. The largest threat, however, probably comes from people who left the ship before the nature of the outbreak was recognized, such as one passenger who was evacuated at St Helena and flown to South Africa, who has since died. Many passengers have since returned to their home countries, with most being placed in quarantine.

The slow spread of the virus, even within the confines of a cruise ship, suggests it is unlikely to become another COVID-19. Hantavirus is so rare that until recently more people had probably heard of it through a passing reference on Friends than any other media coverage, let alone knowing someone who had been infected. Some Hantaviruses don't cause disease in humans at all. While the low transmissibility is the reason the WHO thinks a crisis is unlikely, the disease is far deadlier than COVID-19, or indeed most respiratory infections, to those who do catch it.

The state of communication between Argentinian health authorities and the WHO following the crisis is unknown, but suspected by public health experts to have been less than ideal. The French health minister, Stéphanie Rist, told the French National Assembly there was no evidence that such a mutation has occurred, but that the strain circulating on the boat has yet to be completely sequenced. However, given the long incubation period and the time passengers spent in contact, it is likely that more infections will come to light.