Sunday, October 04, 2009

Swine flu vaccine myths 'busted' by Australian experts

Fear and misinformation have clouded the need for widepread swine flu vaccination, experts said today, at a 'mythbusting' seminar convened by vaccine manufacturer CSL.

Though the pandemic has faded for now, it could return to Australia's shores as early as February next year and the country ideally needs more than half the population vaccinated by that time, said Professor Robert Booy of the National Centre for Immunisation Research and Surveillance.

Immunisation and influenza experts including Professor Booy, Professor Alan Hampson of the WHO's Influenza Specialist Group and Professor Terry Nolan of the University of Melbourne said they wanted to dispel some of the myths that had sprouted around the vaccine, through underinformed media reports and anti-vaccination campaigners. They emphasised the risk, especially to young people and pregnant women, if the virus returns in force next year. And they speculated that it was only the expertise and new techniques in Australia's hospital intensive care wards that prevented a much higher death toll this year.

MYTH: The swine flu vaccine has been rushed through without the normal tests.

FACT: The vaccine took just as long to prepare as the usual seasonal flu vaccine, has been approved by the Therapeutic Goods Administration, and has been subjected to greater scrutiny than the usual flu vaccine.

MYTH: Swine flu is so mild that you might as well just catch it and not bother with the vaccine.

FACT: The number of deaths caused by swine flu could be up to ten times those that we know about, because it might have exacerbated other underlying diseases. It is particularly dangerous in young people and pregnant women.

MYTH: I had the flu this year, so it was probably the swine flu and I'm immune.

FACT: With a new pandemic, especially in children, the immune response may not be strong enough to prevent another infection.

MYTH: In 1976 a swine flu vaccine in the USA caused paralysis (Guillian-Barre Syndrome) and it could do again.

FACT: It was a one-off. The original effect was only an additional one case of GBS per 100,000 people vaccinated. The modern vaccine is very different, and no subsequent vaccines have been linked to GBS. In fact, research suggests vaccination may REDUCE the likelihood of getting GBS, which can be caused by an infection.

MYTH: The use of multi-dose vials poses an infection risk.

FACT: Not if GPs follow standard infection control procedures. Previous cases of MDV-related infection are decades old. The only real risk is the potential for some of the vaccine to be wasted, because the vials must be thrown away a day after opening.

MYTH: The vaccine contains dangerous amounts of mercury.

FACT: The multi-dose vials contain a small amount of thiomersal, a mercury-based preservative. It is in such small trace amounts — similar to the amount of mercury in some foods — that there is no credible evidence it poses any risk whatsoever.

MYTH: The vaccine is unsafe for pregnant women to use.

FACT: There is no reason to believe there would be unusual risks for pregnant women. In fact, because the flu is most dangerous to that group, they should be encouraged to vaccinate.

MYTH: The vaccine is not safe for children.

FACT: Tests to establish the appropriate dose for children are still under way, but there is no reason to think they will turn up any problems.

MYTH: People with egg allergies should not have the vaccine.

FACT: Most egg allergies are only mild, and the vaccine will be safe for these people.


Cockroach inspires cheap artificial heart

A ground-breaking £1,500 artificial heart inspired by the anatomy of the cockroach could revolutionise human cardiac care, scientists in India believe.

The development of a robust, affordable and safe synthetic heart remains one of the holy grails of biomedical engineering amid a shortage of donated organs and rising levels of heart disease. In Britain, critically ill adults wait an average of 103 days and children 143 days for a donated heart, according to the NHS. In India, heart disease will end more lives per year than all infectious illnesses combined, including diarrhoea, tuberculosis and malaria, by 2015, World Health Organisation figures suggest, as Western lifestyle diseases take a grip.

The heart may appear quite a simple organ: a powerful muscle that acts as a pump to move blood around the body. But efforts to replicate it have floundered. The two artificial hearts available in the US today are expensive, costing at least $50,000 (£30,000) apiece. Both have problems, with patients vulnerable to infections and strokes, experts say.

Sujoy Guha, a biomedical engineer at the Indian Institute of Technology, Kharagpur, believes that the most critical problems are a result of artificial hearts attempting to mimic the real thing. The human heart has four chambers, but only the left ventricle is responsible for building the pressure that moves blood around the body. Depending on one chamber to do the hard work places this part of an artificial heart under enormous strain.

Dr Guha likens the process to trying to scale a four-foot rise in just one bound. “Do it too often and your knees will give way,” he said. “Much better to use a series of small steps.”

The sudden build-up of pressure inside conventional artificial hearts can also damage blood cells, Dr Guha said. This can lead to clotting and strokes, and means that patients must be given anti-coagulants, which place them at risk of severe bleeding. By contrast, his prosthetic heart builds pressure in stages, through five chambers — a model based on the anatomy of a cockroach. He has been working on his prototype heart, which is made from titanium and plastic and runs on batteries that can be recharged from outside the body, since the early 1960s.

The heart of the cockroach has 13 chambers, which build pressure in a series of steps. If one fails, the animal still continues living. “When I was learning my biology I became fascinated by the cockroach,” Dr Guha told The Times. “It is hardy [and] survives extreme conditions. It came into this world before humans and will survive beyond us.”

Dr Guha is testing his device on goats, and hopes to move on to humans in the next 18 months. He believes that his artificial heart could be available in five years. He hopes to make one available for about £1,500, a feat he says is possible because his project is government-funded and will not have to pay research costs.


How to make a perfect cup of tea in the traditional English way

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