# 3484
In the northern hemisphere, during the summer months, influenza is normally pretty much non-existent.
No doubt a few cases are imported, and even enjoy limited localized spread, by travelers returning from the tropics (where is is always influenza season) or the southern hemisphere.
But widespread transmission of influenza during our summer season only seems to happen with a pandemic strain. We saw that in 1918, and we are seeing that again this year.
That, and studies showing that this H1N1 virus replicates much better than seasonal flu does deep in the lungs, has scientists and pandemic planners more than a little wary.
Despite reassuring statements in the press to the contrary, this isn’t your father’s influenza. There are distinct differences between it, and seasonal flu.
In today’s Guardian, we get this assessment of the risks of this pandemic from Dr Alan Hay, director of the London-based World Influenza Centre.
Swine flu: Health experts 'surprised' by spread of virus in the UK
• Scientists were 'caught napping' by outbreak, says flu expert
• Under 30s at greatest risk from pandemic
Swine flu experts have warned the virus could become more deadly. Photograph: AP
One of the world's most respected influenza scientists said today that health officials had been surprised by the spread of swine flu.
Dr Alan Hay, director of the London-based World Influenza Centre, said the extensive summer outbreak in Britain had not followed expected patterns and warned the Department of Health needed to be prepared for a more deadly form of the disease.
"We have been a little surprised by the degree of spread of this virus. A few weeks ago we anticipated that this was going to be a short series of outbreaks that would probably peter out before reappearing in the autumn or winter and that has proved not to be the case."
Hay added:
• Some of the background health concerns noted against flu deaths would not have been fatal, noting an American case where the underlying cause was obesity.
• The flu surveillance community had been "caught napping" by the emergence of the swine flu outbreak as most resources were concentrated on guarding against a bird flu pandemic.
• He was concerned about the emergence since 2007 of drug-resistant flu, which could impact on the pandemic virus.
