Pre-pandemic H5N1 vaccines can save lives -expert
SINGAPORE, May 3 (Reuters) Scientists today called for more effort and funding in developing vaccines to combat what they fear would be a pandemic triggered by the H5N1 bird flu virus that could kill millions of people.
Such ''pre-pandemic vaccines'' are designed based on current strains of the virus and might not be perfect fits for the eventual pandemic strain, but scientists say they would help save lives and buy time until a pandemic vaccine is developed.
''Is the world stockpiling pre-pandemic vaccines? That is more valuable than people realise. It may not necessarily protect you from infection with the next plague or the next variant, but it will probably stop you from dying,'' influenza expert Robert Webster from the St Jude Children's Research Hospital told Reuters in an interview.
''It should confer protection from death though you will still get sick and may get very sick but you have a better chance of survival than if you do not receive a pre-pandemic vaccine.'' Companies developing pre-pandemic vaccines told a bird flu conference organised by the Lancet medical journal in Singapore today that human clinical trials have so far proven safe, but these require multiple doses -- at high dosages -- which will inevitably strain global capacity.
At current production capacity, the world can only produce about 300 million doses of human flu vaccines a year -- most of which health experts say might go only to the wealthiest countries.
FOR EVERYONE? Melanie Saville of Sanofi Pasteur, which has just completed its first phase of a human clinical trial on a vaccine based on a Vietnam strain of H5N1, said it planned to move into the second phase of clinical trials before the end of May in Britain and Belgium.
''The data is encouraging but we're not at a stage where we can say more,'' Saville said, adding that the company would try to collaborate with governments to develop pre-pandemic vaccines.
However, even these companies say not everyone will get their hands on pre-pandemic vaccines.
''We are by far in a situation where it is difficult to conceive having provisions for everyone in the world,'' said Martine Denis, Influenza Programme Head for GlaxoSmithKline Biologicals in Belgium.
She said it would take three to five years to build additional plants, which would require huge investments.
''You need trained personnel, raw materials and validated equipment,'' Denis said.
The companies said they would try to spare the amount of antigens needed in the next generation of vaccines. Antigens are substances that stimulate an immune response, especially the production of antibodies.
It takes anywhere from four to six months after the onset of a pandemic before any vaccine can be rolled out to the market and pre-pandemic vaccines could at least help protect a population in the meantime.
James Campbell, assistant professor of pediatrics at the University of Maryland Center for Vaccine Development, said a pre-pandemic vaccine could potentially be included in an annual flu vaccination.
But there are risks.
Any pre-pandemic strain could still cause rare side effects if used en masse, Campbell said, and administering any kind of pre-pandemic vaccine was a decision that public health officials would have to make.
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