Avian Flu - What we need to know

Vietnam update

In an impressive burst of action, Vietnam, once the epicenter for bird flu, has temporarily stamped out the disease: no people infected since November, and no poultry outbreaks since December.

The poor communist nation says it accomplished this feat by vaccinating millions of chickens and ducks, slaughtering millions more, by being honest with international health officials, and by educating its citizens.

There were even crackdowns on local delicacies, like duck blood pudding, believed to be the source of at least one death.

[...] Vietnam spent $18.9 million vaccinating 120 million birds last year and plans to immunize 160 million more birds, said Hoang Van Nam, deputy director of the Department of Animal Health. Eighty percent of the poultry sampled after vaccination had enough immunity to protect against the disease and none was found to be carrying the virus.

China claims to have vaccinated all of its 14 billion domestic birds, but it has continued to see outbreaks and human infections. Last week, Shanghai logged its first human bird flu death, bringing the human toll in China to at least 11, according to WHO.

Widespread immunization requires thousands of workers who must keep the vaccine chilled and return to farms to give booster shots three or four weeks after the first inoculation. A third injection is given four months later to poultry raised up to a year. But many birds have much shorter life spans, meaning the cycle constantly starts over.

Read more at CNN.

Avian flu vaccine safe but not very effective

The vaccine, which the United States already is stockpiling in the event of a pandemic, was given to 451 healthy adults between the ages 18 and 64, making it the largest such study to date.

[...] Of the participants given two shots of the highest dose of the vaccine 28 days apart, only 54 percent of them had adequate protection from the virus when researchers tested their blood for antibody response. Not all participants were given the same dosage.

Researchers were trying to determine if the vaccine is safe and what dosage would provide sufficient protection from the virus should it become pandemic. The ongoing clinical trials are being funded by the National Institutes of Health.

[...] the study, published in the March 30 edition of the New England Journal of Medicine, shows that while the shot is safe, only about half of those receiving the highest dose of the vaccine -- 90 micrograms -- produced enough antibodies to stave off H5N1 bird flu, if they were exposed.

The seasonal flu shot, by comparison, provides adequate protection in 70 to 90 percent of those receiving one 15-microgram dose of the vaccine.

Source, here is the NEJM paper (available for free). Effect Measure has more.

Using horse antibodies to fight bird flu

Chinese scientists have produced antibodies in horses that are an effective treatment for bird flu – at least in mice.

Jiahai Lu at Sun Yat-sen University in Guangzhou and colleagues repeatedly inoculated horses with a chicken vaccine against H5N1 bird flu to make them produce antibodies.

They then collected the horses’ blood, separated out the antibodies and split them to make them less likely to cause an allergic reaction when injected into a human. When they injected mice with a tenth of a milligram of these antibodies 24 hours after they had been given an otherwise lethal dose of H5N1, all the mice lived.

In theory, such antibodies could be made quickly against a pandemic strain of H5N1, potentially saving many lives and limiting the spread of the virus. The trouble is that most drug companies have stopped making antibodies this way.

This is because keeping horses is expensive and until now the markets for antiserum have been in poor countries and offer low financial returns. In addition, animal rights campaigners object to the technique.

Companies have instead invested in making modern, monoclonal antibodies using cell cultures. "It would be complex and expensive for a company to hugely scale up its monoclonal production to treat whole populations rather than a few people,” says David Fedson, founder of the vaccine industry’s pandemic task force.

Source.

US working on new vaccine

Federal health officials announced plans Monday for a second vaccine to protect people from bird flu because the virus that is spreading among birds in Asia and Europe has changed significantly in the past year.

The government has several million doses of an earlier bird flu vaccine, but it was based on a sample of virus taken from Vietnam in 2004. The germ is believed to have mutated enough since then that the form now circulating in Africa and Europe may be different, health officials said.

Source. The story should make it clear that this is a race in which we will always be a step slow. For H5N1 to become a pandemic the virus has to mutate a bit more. If a pandemic does hit we may finally get the relevant virus sample, but it will take a long time to develop a new vaccine and even longer to mass produce it with the current technology.

Revere offers a five minute crash course on what you need to know about avian flu, correctly emphasizing that need to stop thinking we can somehow stop a pandemic in its tracks. Good planning, not vaccine stockpiles, will be key. Tyler made the same argument in November.

EU approves poultry vaccine plans

The European Commission gave conditional approval to French and Dutch plans to vaccinate millions of their poultry against bird flu, the first time it has endorsed such moves.

"The vaccination programmes are authorised only for specific birds in specified regions, and will be subject to rigorous surveillance and control requirements," the commission said in a statement.

"These include movement restrictions, strict monitoring of vaccinated flocks to ensure that there is no undetected outbreak of avian influenza, and careful record-keeping."

Source. British officials spoke out against the vaccine today:

"Crucially, though these vaccines protect against disease, they will not prevent birds from becoming infected and shedding virus," Deputy Chief Vet Fred Landeg said in a statement issued by the ministry.

"Because symptoms of disease would be masked, the hidden presence of disease would pose a serious problem," he added.

Today Austria announced the first H5N1 infection in poultry in the EU.

Small dose vaccine trials "encouraging"

Small doses of a vaccine against the H5N1 bird flu virus achieved "encouraging" preliminary results in a trial involving healthy adults, Australia's CSL Ltd. said on Friday.

[...] CSL said it hopes to be able to apply for approval of a prototype vaccine by the end of 2006, after it completes a study testing doses of 30 and 45 micrograms on 800 people ranging in age from 6 months to the very old.

CSL plans to present the full results of the trial, which involved 400 people aged between 18 and 45, at an international meeting in Hawaii in March.

CSL used an aluminum phosphate adjuvant. Other companies have found better immune responses with other adjuvants, however aluminum-based adjuvants are the only additives that are registered for approval around the world, a CSL spokeswoman said.

Source.

New vaccine tested by CDC

Researchers at the U.S. Centers for Disease Control have created a prototype of an avian flu vaccine that could hold significant promise for use in an influenza pandemic.

The vaccine — made by engineering a human cold virus to produce a protein made by the H5N1 flu virus — would likely be quicker to make than standard flu vaccine, induce a better immune response and could be made without reliance on eggs, the researchers said in a study rushed to print by The Lancet, a prominent medical journal.

Influenza vaccine experts unrelated to the work praised the study, but noted as yet the vaccine has only been tested in mice.

Here is the news article, The Lancet was supposed to have the full paper today (requires a subscription).

"DNA" vaccine progress

A new bird flu vaccine made using cleaner technology took just a month to make and completely protected chickens from the deadly H5N1 virus, U.S. researchers reported on Thursday.

The genetically engineered vaccine appears to fulfill the promise of modern influenza vaccine technology being pushed by public health experts who want to improve the slow, old-fashioned methods now used to fight the flu.

The team at the University of Pittsburgh is now putting together a plan to test the vaccine in humans.

Source. See Revere's excellent review of the scientific paper behind the news story.

GlaxoSmithKline to start vaccine trials in April

Drug maker GlaxoSmithKline PLC hopes to start clinical trials in early April for its vaccine against the deadly H5N1 bird flu strain, a company executive said Thursday.

The London-based company would test the vaccine with two different boosters and the first results should come about three months later, said David Stout, president of the company's pharmaceutical operations.

Production is slated to start by year's end, he said on the sidelines of the World Economic Forum's annual meeting.

Source.

California institute reports on progress towards flu vaccine

Cheroutre's concept focused on M2, a protein common to all influenza A viruses, including avian flu strains. Her insight was to suggest using a portion of the M2 protein to immunize Transchromosomic miceTM, which are mice genetically-engineered to produce human antibodies. The TC MouseTM Technology, developed by Kirin's Pharmaceutical Division, allowed researchers to obtain influenza M2-specific human antibodies.

In conducting the research, Gemini scientists used synthetically created pieces of the H5NI avian flu virus, along with a number of other synthesized virus pieces, to analyze the effectiveness of the human anti-M2 antibodies, which had been created from theTranschromosomic miceTM. "In laboratory (in vitro) testing, they found that the anti-M2 antibodies bound to several different influenza strains, including the avian flu virus (H5N1)," Cheroutre said. "This reactivity means that if used in vivo (in a living organism) the infected cells would be recognized by the antibody and destroyed by the immune system." The study also found that a relatively low dose of the antibodies was needed to fight the various flu strains.

While most of the work was done on virus pieces to avoid the risk of using actual viruses, Gemini also tested the M2 antibodies on mice infected with a potentially lethal influenza strain, with similarities to the avian flu virus. "They found that those mice which received the human M2 antibody were protected, while those mice that did not get the M2 antibody would die," Cheroutre said.

Based upon the lab and mice testing, Gemini Science is now initiating pre-clinical studies required for the commencement of human clinical testing of the anti-M2 antibody, said Shinichiro Kato, Ph.D., Gemini's Chief Scientific Officer. Gemini, which is testing the antibody both as a treatment and preventative measure against flu, has expedited the research due to the recent cases of avian flu. Gemini is currently in discussions with the Centers for Disease Control (CDC) about establishing a Cooperative Research and Development Agreement to jointly conduct further research. Gemini's findings were presented Saturday at the 45th annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), which runs through Monday in Washington, D.C.

Read the entire article here, thanks to Bill Kilfoyle for the link.