His laboratory in Birmingham was a World Health Organization Reference and Research Centre for Rotavirus Infections from 1980 until his retirement in 1987.

Flewett received his medical education at Queen's University, Belfast, where he graduated with honours at the end of the World War II in 1945.

[8] This experience proved invaluable twenty-five years later when a laboratory-associated case of smallpox at the Medical School of the University of Birmingham, UK, led to the death of Janet Parker.

[12] But the preparation of thin sections was too cumbersome for routine use, and Flewett and his co-workers showed that these viruses could be seen by electron microscopy directly in faeces.

[13] Flewett and his colleagues in his Birmingham laboratory had observed these viruses in the faeces of sick children before the publication of Ruth Bishop's paper but they failed to realise that they were the cause of the infection.

[14] Flewett wrote: 'At the South Wiltshire Virology Society I met Gerald Woode, then at Compton, in late 1973.

Ruth Bishop, who was the first to describe rotaviruses as a cause of gastroenteritis had suggested "duovirus" because these viruses replicate in the duodenum and, at the time, were thought to have a double protein outer coat.

He also identified two new species of adenoviruses (later called types 40 and 41), as well as confirming the presence of caliciviruses, astroviruses, and faecal coronaviruses.

Two members of Flewett's team were subsequently quarantined but apart from Janet Parker's mother, no further cases of smallpox occurred.

He was a judge for the King Faisal International Prize in 1983, which was awarded to Professor John S. Fordtran, Dr William B. Greenough III and Professor Michael Field, for their work on oral rehydration therapy in reducing mortality and morbidity due to cholera and other acute infectious diarrhoeal diseases.

[24] During these years he travelled widely as a World Health Organization consultant to most countries in which childhood diarrhoea is a major problem.

He established The WHO Collaborating Centre for Reference and Research on Rotaviruses, (known as The WHO Lab), at his laboratory which was supported by The World Health Organization from 1980 until his retirement in 1987.

[27] Flewett was educated at a time when very little was known about viruses and viral illness and when there were no laboratory tests to aid or confirm a diagnosis.