New prospects against avian influenza pandemic

A live but weakened H5N1 avian influenza vaccine, which opens up the prospect of a new generation of vaccines that can fight off strains that have changed from the original form in the vaccine, US scientists said Monday. Two.

Preventing avian influenza epidemic has a decisive meaning in preventing bird flu in humans (Photo: TP) If the next test on people gives similar results on animals, scientists can transfer to study the production of live vaccines to better deal with avian influenza.

The currently available avian influenza vaccine has the disadvantage that only against the H5N1 virus does not change compared to the vaccine used for vaccine production.

In other words, these injectable vaccines only help the body's immune system learn how to detect and kill the H5N1 virus similar to or similar to the vaccine strain.

Once the H5N1 virus changes, the vaccine currently has almost no effect . Therefore, it is only when the pandemic flu occurs with the emergence of the new virus strain that people can start production so that the vaccine according to the current method will work. And the time it takes to produce a sufficient amount for the world needs no less than six months.

Interestingly, the new product, which has been produced since 1997 with the H5N1 virus, has been able to counteract the virus born in 2004 with a different structure than the 1997 structure.

Dr. John Treanor (vaccine specialist University of Rochester, New York, USA commented: 'This new product is very promising, opening a new phase against pandemics with live vaccines'.

Dr. John Treanor
(Photo: cdh.org)

The H5N1 virus used to produce live vaccines is the strains collected from 1997, 2003 and 2004. Live vaccines are tested in mice and mink.

Researchers (National Institute of Allergy & Infectious Diseases, USA, the US National Institutes of Health and MedImmune Inc., a company specializing in live virus production) found that a single dose of live vaccine was enough to help mice. do not die when it is infected with H5N1 virus; Even if it does not produce antibodies, the sign is considered evidence that the immune system has a defense response.

If two doses are given, both rats and mink escape the death scythe when exposed to the H5N1 virus and produce antibodies clearly.

The first batch of human trials was conducted in June 2006 at Hopkins University, Baltimore. However, a scientist said that the experiment was not meaningful because of the small sample size.

If successful on humans, hope to produce vaccines soon before a pandemic. Not only that, the amount of virus needed will be less, consuming less eggs to produce viruses is less than the method of producing vaccines from dead viruses or now inactivated viruses.

But once it goes into mass production if proven effective, vaccine companies can fall into a state of inadequate vaccine availability. There is only one US enterprise in the world (MedImmune Company) and one Russia specializing in the production of live vaccines, the technology is extremely complex and dangerous, almost like putting bombs in the house.

According to Washington Business magazine, the federal government has allowed Gaithersburg Co. to test more than 300 volunteers for new products, the bird flu vaccine is used as a patch on the skin instead of being injected as long.

The principle of this glue is that the vaccine will permeate the outer skin cell into the lymph nodes (lymph nodes) in the body to stimulate the immune system. Before the end of this year, the company also plans to test the second phase on the elderly.

The company has just signed a contract to test the second phase on Americans traveling to Mexico and Guatemala for vaccine against diarrhea and E.Coli infection.

QD