Isao Arita

was a Japanese physician, virologist and vaccination specialist who headed the World Health Organization (WHO) Smallpox Eradication Unit in 1977–85. During this period, smallpox became the first infectious disease of humans to be eradicated globally. He and his colleagues were awarded the Japan Prize in 1988 for this work. He also advised the successful programme to eradicate poliovirus from the Western Pacific region.

Education and early career Arita was born in Kumamoto, southern Japan, in 1926. After gaining his medical degree from Kumamoto Medical School in 1950, he spent a decade working for the Japanese Ministry of Health and Welfare as a medical officer in the Infectious Disease Control section. For part of this time he worked on vaccine control and standardisation, an area in which he received training at the Paul Ehrlich Institute in Germany. He spent around 2 years working on eradication in Liberia, Africa. When American epidemiologist Donald A. Henderson joined the programme in 1966, Arita was the only remaining WHO technical staff member. He was a part of the WHO Smallpox Eradication Unit from its inception in 1966, serving as its deputy director under Henderson's leadership. as well as for increasing the supply of smallpox vaccine used by the eradication programme, and for monitoring and improving vaccine quality. He also undertook research into poxviruses,

After Henderson left WHO in 1976 or 1977, Arita went on to direct the unit. Under his leadership an outbreak of variola minor in the Horn of Africa during the Ethiopian–Somali war was successfully contained, and the final case of naturally transmitted smallpox occurred in October 1977. He administered the process by which smallpox was formally certified by WHO as having been eradicated globally in May 1980. In 1999, he was one of several scientists to argue for the destruction of the remaining stocks of variola virus.

Arita was one of the lead authors, with Frank Fenner and Henderson, of the WHO publication Smallpox and its Eradication, an exhaustive 1460-page volume which was published in January 1988. Arita also wrote his own personal account in the 2010 book, The Smallpox Eradication Saga. An Insider's View.

Later career In 1985, Arita left WHO to direct the Kumamoto National Hospital in Japan, a position he retained until his retirement in 1992. The ACIH aims to promote disease prevention in developing countries, and the body has organised international conferences on vaccines and other topics.

From 1990 until 2004, he chaired the Technical Advisory Group to WHO's Expanded Programme on Immunization and Poliomyelitis Eradication in the Western Pacific Region. The programme was successful in eradicating wild poliovirus from this region in 1997. He also served on the expert committee that certified the eradication of wild poliovirus from North and South America in 1997. Despite these regional successes, the global eradication of polio – planned for 2000

Arita also published on severe acute respiratory syndrome, measles, hepatitis B, hepatitis C and other viral diseases.

Death Arita died on 17 March 2023, at the age of 96.

Awards and honours In 1988, Arita, together with Henderson and Fenner, was awarded the Japan Prize – considered the Japanese equivalent of the Nobel Prize – for his work on smallpox eradication. The Japanese government conferred on him the title of "national treasure".

Selected publications

Books Isao Arita. The Smallpox Eradication Saga. An Insider's View (Orient Longman; 2010) Frank Fenner, Donald A. Henderson, Isao Arita, Zdenek Jezek, Ivan Danilovich Ladnyi. Smallpox and its Eradication (WHO; 1988) (downloadable at )

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