The Japanese government has supplied antiviral drug?favipiravir from its stockpiles to Britain in response to a hantavirus outbreak, health minister Kenichiro Ueno said Monday.

The U.K. Health Security Agency also said ?on Monday that 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 U.K. remained very low.

Britain has accepted passengers, including a Japanese national, from the cruise ship hit by an outbreak of the virus during a voyage in the Atlantic Ocean.

Ueno expressed gratitude to Britain for accommodating the Japanese national on a chartered plane and conducting health checks. ¡°We¡¯ll continue to work closely with the international community to prevent the spread of infections,¡± he said.

According to Japan¡¯s health ministry, the government supplied the drug at the request of the British government based on a bilateral memorandum of understanding.

Neither the U.K. agency nor ?Japanese authorities disclosed details about the number of doses supplied to Britain. The luxury liner at the center 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 U.K.

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.