Page last updated at 11:11 GMT, Wednesday, 29 April 2009 12:11 UK

The quest for a swine flu vaccine

By Clare Murphy
BBC News health reporter

Vials containing samples of the swine flu virus are making their way from the US to a government laboratory north of London. The race for a vaccine is on.

Seasonal flu vaccine
Manufacturers are currently working on the seasonal flu vaccine

It is a global endeavour and will bring the public and the private together, but it could still take several months before a safe and effective jab is available.

Yet amid all this activity, the answer could in fact be right under our noses.

Tests are being carried out to establish whether the current seasonal flu vaccine could provide cross protection against what we are seeing at the moment, as there are similarities between the H1N1 human flu viruses and the new H1N1 swine flu.

If that were the case - and it's certainly not impossible - we would in the words of one virologist be "home and dry".

Been there before

Even if this does not confer protection, the picture does not appear to be a bleak one.

The spread of bird flu amongst humans several years ago sparked fears that a pandemic was imminent. Plans were developed, expertise harnessed and facilities built for mass production.

If this had happened six years ago we would really be in a fix - we are in a better position than we have ever been in the history of this planet to combat this
Professor John Oxford
Barts and the London School of Medicine

The vaccine industry has started to attract new investment and government subsidies after years of being a pharmaceutical backwater.

"It was a fantastic dry run," says Professor John Oxford of Barts and the London School of Medicine.

"If this had happened six years ago we would really be in a fix - we are in a better position than we have ever been in the history of this planet to combat this."

The World Health Organisation says it is already in touch with vaccine manufacturers - although is not at this stage putting in orders - but initial work is already underway in national laboratories.

The US Centers for Disease Control and Prevention, which is looking at the molecular properties of the virus and why it appears to have been more virulent in Mexico is hoping to have produced a "reference strain" to send to vaccine manufacturers around the second week of May.

The same process will take place in the UK, once the Health Protection Agency (HPA) receives samples of the virus at its laboratories in Potters Bar.

"We will take this virus apart and reassemble it with two genes from the swine virus and the genetic information code for a laboratory virus called PR8 which grows very well in hens' eggs and is safe for human infection," said Dr John Wood, from the HPA's National Institute of Biological Standards and Control.

"When we have recreated this new hybrid virus this will be grown in cells and hens' eggs ready to distribute to vaccine manufacturers."

This, he said, should be done within three to four weeks.

Kill not cure

But it may be at least four to five months before a vaccine is ready.

Clearly, if you make a swine flu vaccine and the pandemic doesn't actually occur, we could end up with no seasonal flu vaccine
Chris Viehbacher

Safety is - unsurprisingly - paramount, as vaccines can often be worse than the disease they are trying to combat.

An outbreak of swine flu in 1976 infected 200 people in the US. Only one of them died, but a vaccine administered to 40m people killed 25 and led to 500 others developing Guillain-Barre syndrome, which can be fatal.

For those countries now entering the summer months with the flu season behind them, a delay in vaccine is not a real cause for concern. But in the southern hemisphere where countries are entering their winter months the picture would be different if the outbreak were to worsen.

One way of administering the vaccine could be by adding a swine flu component to the seasonal flu jab given out in the autumn.

But while production facilities are much more extensive than they once were, it could still take several years to produce enough swine vaccine to match global demand if the virus continues to spread and becomes more virulent.

And in the rush to combat swine flu - from which there have been fewer than 10 confirmed deaths - manufacturers still have to keep their eye on producing an effective vaccine for seasonal flu as they do every year.

In the US alone there are an estimated 25-50 million cases reported each year. These result in 150,000 hospitalisations and 30,000 to 40,000 deaths. Worldwide there may be as many as half a million deaths each year.

"Clearly, if you make a swine flu vaccine and the pandemic doesn't actually occur, we could end up with no seasonal flu vaccine," warned Chris Viehbacher, chief executive officer of Sanofi-Aventis.

In any event, swine flu appears to be responding well to anti-viral treatments like Tamiflu and Relenza. These drugs do not attack the virus itself but an enzyme that allows it to spread within the body. Taken promptly, they can reduce the severity and length of the illness.

But production of sufficient quantities - were they needed - could again be problematic, although pharmaceutical giants GlaxoSmithKline Plc and Roche Holding AG have both said they are stepping up production.

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