The cases show the ability of Tamiflu-resistant pandemic H1N1 to spread among healthy people who are not taking the antiviral drug, say scientists from Vietnam's National Institute of Hygiene and Epidemiology and Oxford University's Clinical Research Unit in Vietnam.

All seven cases were passengers on the same 42 hour train journey in Vietnam, who were taken ill within a couple of days of completing their journeys.

Six were from a group of 10 students who met and socialised with each other in the same carriage. The seventh case was a passenger in a separate carriage.

Six of the cases were admitted to hospital for isolation while the seventh was isolated at home.

Press Trust of India - December 14, 2009