Inhaled bird flu vaccine in the works

MedImmune to develop different versions for U.S. government

WASHINGTON - A company that makes an inhaled flu vaccine signed up with the U.S. government on Wednesday to try to make a version of its jabless vaccine for avian flu.

Maryland-based biotechnology company MedImmune will work with top U.S. government influenza experts to develop a new vaccine against the H5N1 avian flu, which has killed 65 people in Asia since 2003.

“The threat of pandemic flu is an urgent health challenge,” Health and Human Services Secretary Mike Leavitt said in a statement.

“This agreement will help speed the process of developing vaccines we will need to fight an outbreak if the avian flu starts to spread rapidly through the human population.”

Injected flu vaccines use a killed version of the virus. The nasal vaccine uses a live but weakened virus.

To make this attenuated virus Dr. Kanta Subbarao and Dr. Brian Murphy of the National Institute of Allergy and Infectious Diseases will splice selected genes from avian flu viruses considered to be a threat into a weakened human flu virus. They will also work with MedImmune scientists to use a process called reverse genetics to make a vaccine.

Experts consider the avian flu the single biggest threat to human health in the world today. The H5N1 virus has killed and forced the destruction of tens of millions of birds and can on occasion be transmitted to people, often killing them.

A slight mutation would enable the virus to be passed easily from person to person and because it is such a new virus, experts believe it would sweep around the world, killing millions of people, if it is not stopped.

A vaccine is the best way but production of influenza vaccines is slow, and they do not work perfectly.

Preparing for future outbreaks
NIAID and MedImmune will try to develop at least one vaccine for each of the 16 variations of a protein found on the surface of all influenza A viruses, called hemagglutinin (represented by the letter “H” in the names of influenza strains, such as H5N1).

This will take years but will help in preparing for future outbreaks, the NIAID said.

Several companies are working on an H5N1 vaccine, and the furthest along in development is France’s Sanofi-Aventis. U.S.-based Chiron Corp. aims to test its H5N1 vaccine later this year and Britain’s GlaxoSmithKline Plc plans large-scale clinical trials in 2006.

These companies, along with MedImmune, also make vaccines against ordinary flu, but they do not protect against avian flu.

Experts would like to have as many options as possible, as influenza spreads quickly once a new strain emerges. It takes months to make a new influenza vaccine and the immunization must match the strain that is actually infecting people, so it is not currently possible to make them up before a new strain emerges.

“An intranasal pandemic vaccine may help facilitate and expedite influenza vaccinations for more Americans in the event of a pandemic outbreak,” MedImmune research and development chief James Young said in a statement.

Two antiviral drugs can help against the infection and may even prevent it if taken at the right time. These are Tamiflu from Switzerland’s Roche Holding AG, known generically as oseltamivir, and GlaxoSmithKline’s Relenza, or zanamivir.

source: reuters