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Experts skeptical of experimental birdflu vaccines
Experts skeptical of experimental birdflu vaccines
2006-02-04
Muzzi.comNews
Two teams working on better vaccines for use against a potential bird flu pandemic have announced progress in the past week, but influenza experts are skeptical.
The two labs both used a human cold virus, called an adenovirus, to carry pieces of DNA from H5N1 flu in a vaccine. Both labs -- one at the U.S. Centers for Disease Control and Prevention and one at the University of Pittsburgh Medical Center -- were able to protect mice against fatal H5N1 infections.
But neither study was even mentioned at a meeting of top U.S. flu experts in Washington this week.
"It's just not that new," Dr. John Treanor, a flu vaccine expert at the University of Rochester in New York, said in an interview. "There are a zillion vaccines that protect in mice. On the grand scale of things, it's nowhere near to being a vaccine you would see in humans."
The H5N1 avian influenza virus has killed or forced the culling of at least 200 million birds and has spread from east Asia across to parts of Europe. It mostly affects birds but it has infected 161 people and killed 86 of them since 2003, according to the World Health Organization.
Experts worry it could mutate into a form easily transmitted between people, causing a pandemic that could kill millions.
If that happens, a vaccine is the best protection. Ideal would be a vaccine that could be produced immediately, or even ahead of time.
But developing new vaccines is a time-consuming and tricky business, and for the next few years the world is stuck with 40-year-old technology, no matter what happens in the lab, the experts, including manufacturers, said.
Researchers rely on an old-fashioned way of making vaccines against influenza that requires the use of chicken eggs and months of cultivation.
KEEPING UP WITH MUTATIONS
And influenza viruses mutate quickly, meaning the vaccine must be reformulated regularly. Because there is little demand for flu vaccine, only a few companies make it and they have not invested in expensive new manufacturing facilities or new technologies.
Several companies and private labs are working on a vaccine against H5N1. But because no one knows how it will mutate, they cannot be sure that any vaccine made now would protect against whatever pandemic strain eventually emerges.
Vaccines using cold viruses, using pure DNA, and using whole inactivated viruses are all being tried.
But because they use completely novel technology, they would have to be extensively tested in humans, who have different immune responses from other animals.
Chris Viehbacher, President of GlaxoSmithKline, which makes flu vaccines, said it would take years to approve entirely new approaches to flu vaccine.
If a pandemic comes before vaccine technology can be improved, Glaxo had counted on using the current vaccine formulation boosted with an aluminum adjuvant, he said in an interview on Tuesday.
Adjuvants are added to vaccines to help increase the immune response and may make it possible to stretch a vaccine supply.
Before boosting production and building new plants in the United States, Viehbacher said drug makers wanted better protection from lawsuits from people who may be harmed, or who may claim they were harmed, by vaccines.
"This industry spent close to $200 million defending themselves against thimerosal litigation," Viehbacher said. "That hasn't exactly been an encouragement to invest."
Thimerosal is a mercury-based preservative used in many vaccines until recently. Some groups claim it may cause neurological disease in some children, including autism.
Many experts dispute this, including the independent U.S. Institute of Medicine after extensive review.
2006-02-04
Muzzi.comNews
Two teams working on better vaccines for use against a potential bird flu pandemic have announced progress in the past week, but influenza experts are skeptical.
The two labs both used a human cold virus, called an adenovirus, to carry pieces of DNA from H5N1 flu in a vaccine. Both labs -- one at the U.S. Centers for Disease Control and Prevention and one at the University of Pittsburgh Medical Center -- were able to protect mice against fatal H5N1 infections.
But neither study was even mentioned at a meeting of top U.S. flu experts in Washington this week.
"It's just not that new," Dr. John Treanor, a flu vaccine expert at the University of Rochester in New York, said in an interview. "There are a zillion vaccines that protect in mice. On the grand scale of things, it's nowhere near to being a vaccine you would see in humans."
The H5N1 avian influenza virus has killed or forced the culling of at least 200 million birds and has spread from east Asia across to parts of Europe. It mostly affects birds but it has infected 161 people and killed 86 of them since 2003, according to the World Health Organization.
Experts worry it could mutate into a form easily transmitted between people, causing a pandemic that could kill millions.
If that happens, a vaccine is the best protection. Ideal would be a vaccine that could be produced immediately, or even ahead of time.
But developing new vaccines is a time-consuming and tricky business, and for the next few years the world is stuck with 40-year-old technology, no matter what happens in the lab, the experts, including manufacturers, said.
Researchers rely on an old-fashioned way of making vaccines against influenza that requires the use of chicken eggs and months of cultivation.
KEEPING UP WITH MUTATIONS
And influenza viruses mutate quickly, meaning the vaccine must be reformulated regularly. Because there is little demand for flu vaccine, only a few companies make it and they have not invested in expensive new manufacturing facilities or new technologies.
Several companies and private labs are working on a vaccine against H5N1. But because no one knows how it will mutate, they cannot be sure that any vaccine made now would protect against whatever pandemic strain eventually emerges.
Vaccines using cold viruses, using pure DNA, and using whole inactivated viruses are all being tried.
But because they use completely novel technology, they would have to be extensively tested in humans, who have different immune responses from other animals.
Chris Viehbacher, President of GlaxoSmithKline, which makes flu vaccines, said it would take years to approve entirely new approaches to flu vaccine.
If a pandemic comes before vaccine technology can be improved, Glaxo had counted on using the current vaccine formulation boosted with an aluminum adjuvant, he said in an interview on Tuesday.
Adjuvants are added to vaccines to help increase the immune response and may make it possible to stretch a vaccine supply.
Before boosting production and building new plants in the United States, Viehbacher said drug makers wanted better protection from lawsuits from people who may be harmed, or who may claim they were harmed, by vaccines.
"This industry spent close to $200 million defending themselves against thimerosal litigation," Viehbacher said. "That hasn't exactly been an encouragement to invest."
Thimerosal is a mercury-based preservative used in many vaccines until recently. Some groups claim it may cause neurological disease in some children, including autism.
Many experts dispute this, including the independent U.S. Institute of Medicine after extensive review.