Doubts over swine flu trends
Friday November 27th, 2009
It is "too early" to say whether the swine flu outbreak has reached its peak in northern countries, an expert said yesterday.
The number of cases in Britain continues to decline, according to the Health Protection Agency, and the same is happening in other northern countries.
According
to Dr Keiji Fukuda, special adviser to the World Health Organisation Director-General,
it may take several weeks before there is a clear downward turn.
Speaking yesterday, he warned that WHO remains puzzled by the mutant virus linked to the first deaths in Norway. The mutation has also been seen in countries such as Brazil, China, Japan, Ukraine and the USA.
He said: "Whether there is a fundamental change in viruses or a turn for the worse in severity, the answer right now is we are not sure. This mutation has been reported in people with severe disease and people with mild disease."
* Closing schools could significantly reduce illness transmission in an epidemic, according to a new analysis.
Dr Niel Hens of Hasselt and Antwerp University, Belgium, and colleagues carried out a survey in eight European countries. They compared opportunities for infection on school days versus weekends and holidays.
The chances of infection were reduced when schools are shut, they report in the journal BMC Infectious Diseases.
Figures from Belgium, England & Wales, Finland, Germany, Italy, Luxemburg, Poland and the Netherlands were used in the study.
Dr Hens explained: "Mathematical models of how infectious diseases spread from person to person through close contacts rely on assumptions regarding the underlying transmission process.
"One of these assumptions is that school closure will result in reduced exposure for children. Until now, however, the exact impact of this measure has not been proven".
The team estimated the effects of school closure on the number of close contacts people make in a day.
Between-generation mixing becomes more frequent on weekends but same age mixing becomes relatively less frequent, leading to a ten per cent overall reduction in contacts when schools are closed, the figures showed.
Dr Hens said: "Children are important spreaders of many close contact pathogens due to their frequent and intimate social contacts, their general hygiene, and perhaps their increased shedding. The reduced opportunity for contact we describe here would be a great benefit in a pandemic situation".
This strategy would have significant impact on disease transmission - a drop of about 21 per cent, the authors conclude.
But "the expected large macroeconomic costs of school closures would have to be balanced against these benefits", they add.
Hens, N. et al. Estimating the impact of school closure on social mixing behaviour and the transmission of close contact infections in eight European countries. BMC Infectious Diseases (in press).
Tags: Asia | Child Health | Europe | Flu & Viruses | Respiratory | Traveller Health | UK News | World Health
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