Japan National Institute of Infectious Diseases said the authorities found a new strain of coronavirus in four passengers arriving from Brazil.
The new variant has similarities to strains found in the UK and South Africa, NIID said in a statement on Sunday. Information about the new variant is limited to its genetic makeup and it is difficult to determine immediately how infectious the strain is or the effectiveness of current vaccines against it, the institute said.
In a separate statement, the Japanese Ministry of Health said the four passengers who arrived from Brazil at Haneda airport in Japan on January 2 were later diagnosed with a variant of the virus. A man in his 40s, who was asymptomatic on arrival, was hospitalized because his respiratory system worsened.
NIID informed the World Health Organization about the new strain, Yomiuri Shimbun reported, adding that the institute is investigating whether the variant causes more serious cases.
(Updates with patient details in the third paragraph)