The swine flu pandemic is "considerably less lethal" than feared, with a death rate lower than 0.1%, research by England's chief medical officer shows.
Twenty-six people have died for every 100,000 cases in England, an analysis of deaths to November 8 revealed.
About 1% of the population in England has had swine flu with symptoms, of which 0.026% died, the research added.
Sir Liam Donaldson, the Government's chief medical officer for England, led the study, published online in the British Medical Journal (BMJ), which described the low death rates as "fortunate".
His study concluded: "The first influenza pandemic of the 21st century is considerably less lethal than was feared in advance."
Sir Liam wrote, however, that a lower impact than feared was not justification for "inaction". It was right to vaccinate people at risk - such as those with asthma, diabetes, heart disease and pregnant women - and to extend the programme, he went on.
"Viewed statistically, mortality in this pandemic compares favourably with 20th century influenza pandemics," he said. "A lower population impact than previous pandemics, however, is not a justification for public health inaction. Our data support the priority vaccination of high risk groups.
"Given that a substantial minority of deaths occur in previously healthy people, there is a case for extending the vaccination programme and for continuing to make early anti-viral treatment widely available."
The paper showed the estimated death rate was lowest among children aged five to 14, with around 11 deaths per 100,000 population. It was highest for those aged over 65, with 980 per 100,000. In the 138 people in whom the confirmed cause of death was pandemic flu, the typical age at death was 39.
The analysis showed many of the patients who died were high risk and would have been eligible for vaccination.
