Swine flu - new insights

Tuesday December 29th, 2009

Closing schools and vaccinating children and teenagers would have been the best way to control the swine flu epidemic, researchers reported last night.

The study, in the Proceedings of the National Academy of Sciences, is the latest to suggest that the spread of the disease among children and teenagers was critical to fuelling the epidemic.

Jacco Wallinga, a public health expert from Bilthoven, Netherlands, argues there are general principles that can be used to control an epidemic.

These involve targeting those people most at risk of infection - using both vaccination and "social distancing".

"The approach to best allocate scarce resources works best if there are observable differences in the risk of infection between various age groups early in the epidemic," the researchers write.

* Meanwhile Brazilian researchers have reported the findings of detailed post-mortem autopsies of swine flu victims.

The study shows three different ways in which the H1N1 virus led to fatal damage to the lungs.

The findings come from a study of 21 people who died from the disease in Sao Paulo, Brazil, aged between 30 and 59. About three quarters of the patients already had cancer or heart disease - but the others were previously healthy.

Researcher Dr Thais Mauad reports that unlike other flu patients, most victims developed lung disease first and had shown less sign of fever and aching joints - the normal symptoms of flu.

The study found that in some patients there was an over-reaction of the immune system - which may have been responsible for damaging the lungs.

Dr Mauad said: "We would like to deepen our efforts into the understanding of the immune responses in cases of severe infection. This could ultimately lead to new therapeutic approaches."

Dr John Heffner, an American Thoracic Society expert, said: "This suggests that an overly vigorous host inflammatory response triggered by the viral infection may spill over to and damage lung tissue, thereby causing acute lung injury and fatal respiratory failure."

American Journal of Respiratory and Critical Care Medicine
"Optimizing infectious disease interventions during an emerging epidemic," by Jacco Wallinga, Michiel van Boven, and Marc Lipsitch, Proceedings of the National Academy of Sciences #09-08491

Tags: Child Health | Europe | Flu & Viruses | North America | World Health

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