The H5N1 strain has not evolved yet into a form that passes easily between humans, but studies suggest some vaccines might help protect people from death if a pandemic strain does emerge.

Several countries have ordered or are negotiating to stockpile pre-pandemic H5N1 vaccines, which some experts recommend to immunize health care workers, firefighters and other essential staff before a pandemic breaks out.

David Salisbury, director of immunization at Britain's Department of Health, told the conference it would take 4-6 months for the first vaccine doses to emerge from factories, and up to a year to produce enough for the recommended two doses.

"During this time, at least the first pandemic wave will be over, and the second and third waves, should they occur, may also be over before significant numbers of individuals can be vaccinated," he said.

Salisbury said some data on vaccines had shown that "even if poorly matched against the pandemic strain, they may play a valuable role in minimizing disease, reducing transmission and even aborting a pandemic".

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Kieny said the WHO did not yet have an official position on pre-pandemic vaccination, which she called a "tricky issue".

"We need to take into consideration that immunizing part of your population, especially groups on the front line to combat the pandemic, might be a good benefit," she said.

"But you have to weigh that against the risk of immunizing against a pandemic that is not there," she said, referring to the 1976 swine flu scare in the United States.

That year, millions of Americans were vaccinated against swine flu after an outbreak at a U.S army base triggered fears of a wider pandemic. It never occurred and the vaccine was blamed for a rise in cases of a rare neurological illness.

WHO officials said several projects were now underway to boost production capacity for vaccines to protect against bird flu and other viruses with pandemic potential.

The U.N. health agency launched a plan in October to increase global flu vaccine capacity, which is expected to rise to 780 million doses by 2009 under current expansion plans, still far short of what would be needed to fight a global pandemic.

The strategy calls on governments to increase normal flu vaccination campaigns to encourage companies to raise capacity.

Drug makers could also be paid to keep capacity idle for pandemic vaccines. It also urges study of more potent vaccines to reduce the number of recommended doses to one from two.

The plan could cost $3-$10 billion over the next decade.

"None of these strategies will be able to fill the gap in the immediate short term but, starting now, first results may be seen in three to five years," the WHO's Alejandro Costa said.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.

Half of world's stomach cancer victims in China

Last Updated: 2006-12-06 11:00:58 -0400 (Reuters Health)

BEIJING - China accounts for about half of the global annual death toll from stomach cancer due to the Chinese taste for pickled and smoked food and unabashed enthusiasm for smoking, the official Xinhua news agency said.

The disease kills about 300,000 people in China a year and there are 400,000 new cases reported annually, Xinhua said in a report seen on Wednesday.

Only lung and liver cancer kill more people in China, it quoted Jin Maolin, a doctor at Peking University, as saying.

Though men aged over 50 are most at risk, the number of women in rural areas who have contracted stomach cancer has risen 25 percent in the past five years, Jin said.

Chinese people need to eat more fresh fruit and vegetables and cut down on salted and pickled food -- very popular in China -- as well as smoking and drinking to reduce the risks, he added.

The World Health Organization and Chinese Health Ministry warned earlier this year that a surge in chronic diseases such as cancer and diabetes due to changing lifestyles could kill up to 80 million people in China in the next decade.

Chinese urban residents today eat double the amount of meat they did 20 years ago and both men and woman were smoking at an earlier age, the health ministry said.

The WHO wants developing countries, where most such deaths occur, to copy Western nations by discouraging tobacco use and curbing salt, sugar and saturated fats in food.

They could have their work cut out for them in China, home to the world's most enthusiastic smokers who smoke about two trillion cigarettes a year, according to the Chinese government.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.