As the World Health Organisation (WHO) reclassifies the outbreak of swine flu to the level of a global pandemic, health officials in Scotland have announced they are to take a more flexible yet aggressive approach to fighting the disease. 

The WHO raised the classification of the swine flu outbreak to phase six, the  highest level of its classification, meaning the pandemic is now a global epidemic involving a large majority of countries.

The announcement came as Scotland saw its number of swine flu cases rise to 337 after 26 new patients were announced.

The majority – 18 – of the new instances of the virus are in NHS Greater Glasgow and Clyde. Three new cases are in NHS Highland, two in NHS Lothian, and three in NHS Lanarkshire. There are nine people being treated in hospital, all of them in Greater Glasgow and Clyde. A further probable case is being investigated in NHS Grampian in addition to the 659 possible cases being probed.

It is the first official flu pandemic in 41 years, and follows a 400% increase in cases - to more than 1,200 people - in Australia in the past week.  Three flu pandemics have occurred in the last century. In the most recent case, the Hong Kong flu, a total of 33,800 people died between September 1968 and March 1969.

Details of the revised strategy in Scotland, released by the Scottish Health Secretary, followed a meeting of the UK emergency committee Cobra. Nicola Sturgeon told MSPs the new approach will include using clinical diagnosis instead of lab testing in "high probability" cases, such as when a person has come in close contact with a confirmed case.

In a statement, Ms Sturgeon said: "A move to level six means that countries need to be ready to implement pandemic plans immediately."

Scotland - as well as Mexico, the US and Australia - are among the areas that are swine flu hot-spots.

The west of Scotland is the prime focus of the outbreak here. Seventeen schools are closed or partially closed, all in the west.

RESOURCES

World Health Organisation: Swine flu facts

World Health Organisation: Pandemic influenza phases

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Swine flu - a timeline

The Health Secretary said anti-viral drugs will continue to be given to those in Scotland with the swine flu bug but the preventative use of the drugs will be conducted in a more targeted manner. Also, contacts of flu cases will be restricted to those most at risk.

Ms Sturgeon, who told MSPs she was suffering from a cold, said the policy of trying to slow the spread of the virus had been successful, and in areas where there were only a small number of isolated cases, current containment levels would continue.

Where there were more sizeable clusters and evidence of "community transmission" - such as in Dunoon, Glasgow and Paisley - that approach became less effective as it involved giving anti-virals to "very large" numbers of people, many of whom were not ill.

The "refinements" to the swine flu containment strategy include:

- Clinical diagnosis rather than laboratory testing in high probability cases;

- Continued antiviral treatment of all those who have the virus but a more targeted preventive use, based on local risk assessment and limited to contacts considered most at risk of contracting the virus;

- The restriction of contact follow-up to those most at risk.

She said the strategy was in line with expert advice but added:

"There will come a point when even this more flexible approach to containment will no longer be effective and the focus will shift from containing the spread of the virus to mitigating its impact."

A vaccine to stop the virus is being developed for world-wide distribution. Researchers believe it may be available as soon as autumn.

Dr Harry Burns, Scottish Chief Medical Officer, said: "We'll start vaccinating those groups of the population most at risk and most likely to spread it. We'll be driven in those decisions by the science, but my guess is that young people will be high on the list."