Britain gets experimental drug from Japan to bolster hantavirus response

* Favipiravir delivered from Japan to UK for experimental hantavirus treatment, ​UKHSA confirms

* Drug ⁠use is experimental, with limited evidence and ​no established protocol, experts note

* No details disclosed on quantity of favipiravir doses received from Japan

* WHO says outbreak involves Andes virus, no ​signs ‌of increased transmissibility or pandemic risk

LONDON, May 18 (Reuters) - Britain has received supplies of the antiviral drug favipiravir from ⁠Japan as part of its ongoing response to a deadly ⁠hantavirus outbreak linked to the Hondius cruise liner, ​the UK Health Security Agency said on Monday.

UKHSA said it accepted delivery of the drug, which remains experimental for use to treat hantavirus, over the weekend and that the supplies would bolster treatment stocks, even though the ​risk of ‌wider transmission in the UK remained very low.

Neither the UKHSA nor Japanese authorities disclosed details about the number of doses supplied to Britain. The luxury liner at the centre of the outbreak docked at the Dutch port of Rotterdam on Monday, where authorities disembarked crew members and medical staff. Three people have ​died from eight confirmed cases and two probable cases linked to the ship.

There is no specific therapy for ‌hantavirus, which is primarily spread by rodents but can be transmitted between people in rare cases and after prolonged, close contact. Treatment usually focuses on supportive ‌care such as rest and fluids, while some patients may need breathing support. In Japan, favipiravir is sold under the brand name Avigan by a Fujifilm unit, Toyama Chemical, to treat seasonal flu. The drug, which ​works by blocking a key enzyme that many viruses need to multiply, is not licensed for use in the United Kingdom.

Use ‌of favipiravir in hantavirus would generally be considered experimental or compassionate rather than standard care, and most likely to treat severe infection early on, said Piet Maes, a virologist at the University of Brussels.

Maes said evidence ⁠so far ⁠comes only from lab and animal studies, with no strong human trial ‌data showing the drug works against hantavirus. There is no internationally established clinical protocol recommending its routine use for hantavirus.

The outbreak involves ​the rarer type of ​hantavirus called the Andes virus, which is the only strain known to ‌spread between people, though typically only after close and prolonged contact.

World Health Organization officials said they have not identified changes that would make the virus more transmissible or severe, and that the outbreak does not pose a pandemic threat.