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Second Bird Flu Vaccine Under Development, U.S. Researchers Say

An experimental vaccine developed to prevent a strain of avian influenza that has infected humans, H9N2, is going into production and testing with backing from the National Institute of Allergy and Infectious Diseases (NIAID), according to an August 17 NIAID press release.

The U.S. Centers for Disease Control has developed a potential vaccine from an inactivated strain of H9N2, which infected a number of people in Hong Kong in 1999 and 2003, according to the press release. NIAID has awarded a contract to Chiron Corporation, a company that makes human vaccines used in the U.S. population during flu season, to manufacture the vaccine at its plant in Siena, Italy. A separate NIAID project is targeting the H5N1 strain of avian influenza, which has caused 27 deaths this year.

"Because avian influenza viruses like H9N2 have not previously circulated widely among humans, we are likely to have limited, if any, immunity against them," said NIAID's Linda Lambert. "Understanding through clinical trials the safety of the vaccine and the dosage level that will generate a protective immune response is critical."

The test of the potential H9N2 vaccine is a part of NIAID's ongoing effort in the Pandemic Influenza Preparedness Program, which promotes combined efforts between U.S. and international companies to strengthen global capacity to contain and control major regional or global flu epidemics.

Following is the text of the NIAID press release:

National Institute of Allergy and Infectious Diseases
National Institutes of Health

Tuesday, Aug. 17, 2004

CONTRACT AWARDED TO DEVELOP VACCINE AGAINST H9N2 AVIAN INFLUENZA

Contract Part of NIAID Pandemic Influenza Preparedness Program

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has awarded a contract to Chiron Corporation of Emeryville, CA, for the production of an investigational vaccine based on an H9N2 strain of avian influenza virus that has infected humans and has the potential to trigger a modern-day pandemic.

This project, which is part of the NIAID Pandemic Influenza Preparedness Program, is the second recently announced by NIAID that supports the development and production of a candidate vaccine against a pandemic strain of avian influenza. The other NIAID project targets the H5N1 strain that has resurfaced in Asia after an outbreak earlier this year. In 2004, H5N1 has caused 27 deaths.

In 1999 and 2003, an H9N2 influenza strain caused illness in three people in Hong Kong. Scientists are concerned about H9N2 and other emerging types of avian influenza viruses because as they spread--most commonly through poultry--they continually mutate, increasing chances that they may infect humans, evade the body's immune response and become more lethal. Of greatest concern is that these ever-changing avian viruses could develop the ability to spread from person to person, resulting in a fast-moving, global pandemic.

"Given the poor condition of public health systems in many developing regions and the ubiquity of modern air travel, the consequences of a widespread outbreak of avian influenza in humans could be severe," says Anthony S. Fauci, M.D., director of NIAID. "Information generated under this contract will be important for preparing our nation and the world against new influenza viruses with pandemic potential."

Chiron Corporation will produce the H9N2 vaccine at its manufacturing facility in Siena, Italy. The company will prepare different dosages of the vaccine, which is based on an inactivated strain of the H9N2 virus developed by the Centers for Disease Control and Prevention. Some dosages will contain Chiron's MF59 adjuvant--a substance designed to boost the vaccine's protective effect.

The company will produce up to 40,000 doses of vaccine with and without the MF59 adjuvant for clinical trials that will be conducted by NIAID. These trials are currently slated for early next year.

"Because avian influenza viruses like H9N2 have not previously circulated widely among humans, we are likely to have limited, if any, immunity against them. Understanding through clinical trials the safety of the vaccine and the dosage level that will generate a protective immune response is critical," says Linda Lambert, Ph.D., who oversees the clinical influenza research program funded by the Division of Microbiology and Infectious Diseases at NIAID. "By comparing the vaccines with and without the MF59 adjuvant, we can determine if the adjuvant significantly augments the protective effects of the vaccine, enabling us to use lower doses and thereby extend the vaccine supply."

Dr. Lambert says that this contract follows one of the key tenets of the NIAID Pandemic Influenza Preparedness Program that supports working with both U.S. and international companies to develop and evaluate the safety and effectiveness of vaccines against influenza viruses with pandemic potential. Results from this project will not only provide important public health information, but may also help make new types of influenza vaccines available to the public.

"A major component of our strategy is to partner with private-sector companies around the world to develop and clinically test promising new vaccine technologies," she says. "The more studies we can also do with novel types of avian influenza strains such as H9N2 and H5N1, the more likely it is that we may begin to identify patterns that allow us to counteract all of them."

NIAID is a component of the National Institutes of Health, an agency of the U.S. Department of Health and Human Services. NIAID supports basic and applied research to prevent, diagnose and treat infectious diseases such as HIV/AIDS and other sexually transmitted infections, influenza, tuberculosis, malaria and illness from potential agents of bioterrorism. NIAID also supports research on transplantation and immune-related illnesses, including autoimmune disorders, asthma and allergies.