Sunday, July 16, 2006

Work on Pandemic Flu Vaccines Must Start Now, WHO Report Says

Work on Pandemic Flu Vaccines Must Start Now, WHO Report Says
July 15 (Bloomberg) --

Work on vaccines used to protect against a flu pandemic must start immediately, even though the effectiveness of the treatments might not be known until after a global outbreak ended, the World Health Organization said.

Randomized trials of candidate pandemic vaccines will be important in gauging their safety and gaining regulatory approval, the Geneva-based WHO said in a report published yesterday in the Weekly Epidemiological Record.

``Internationally coordinated preparatory work for these trials should start immediately, as little time would be available for putting the needed infrastructure in place after the start of the pandemic,'' the report said.

Pharmaceutical companies, including Sanofi-Aventis SA, GlaxoSmithKline Plc, MedImmune Inc. and CSL Ltd. are racing to produce treatments for use in a pandemic amid concern over the H5N1 strain of avian influenza, which has infected at least 230 people in 10 countries in Asia and the Middle East, killing 132.

Yesterday, Indonesia confirmed its 41st fatality after tests confirmed the H5N1 virus killed a 3-year-old girl earlier this month.

Governments and international health authorities are trying to stem the spread of H5N1 to reduce opportunities for the virus to mutate into a pandemic form.

The Food and Agriculture Organization of the United Nations will open a crisis management center in Rome later this month to help improve control of H5N1, which spread in domestic fowl and wild birds to at least 55 countries since late 2003.

Crisis Center

The center, to be run by the UN agency in collaboration with the Paris-based World Organization for Animal Health, will provide animal disease analysis and deploy international resources to prevent and contain dangerous animal diseases, the FAO said in an e-mailed statement yesterday.

A pandemic can start when a novel influenza A-type virus, to which almost no one has natural immunity, emerges and begins spreading worldwide. Experts believe that a pandemic in 1918, which may have killed as many as 50 million people, began when a lethal avian flu virus jumped to people from birds.

Shots produced each year for seasonal flu won't be effective in a pandemic because the vaccine needs to closely match the pandemic virus, the WHO said in a statement on its Web site.

At least four strains of bird flu are capable of spawning the next pandemic, including the H5N1 virus, according to virologist Robert Webster, the Rosemary Thomas professor at St. Jude Children's Research Hospital in Memphis, Tennessee.

Vaccine Delays

Although a vaccine against the H5N1 virus is under development in several countries, none is ready for commercial production and no vaccines are expected to be widely available until several months after the start of a pandemic, the WHO said.

``Effectiveness of pandemic vaccines will not be known before the pandemic and possibly only after it is over,'' the report in the Weekly Epidemiological Record said. ``In addition, unexpected adverse events, whether coincidental or vaccine- related, will occur that may lead to anxiety and may affect vaccine uptake.''

The UN health agency said it could play a critical role in assisting countries collect and review safety data on pandemic vaccines.

``WHO's role in gathering information on the safety profile of candidate pandemic vaccines from clinical trials should be enhanced,'' it said. The report follows a meeting in Geneva last month of the Global Advisory Committee on Vaccine Safety, an expert clinical and scientific advisory body.

The committee reviewed possible measures to overcome obstacles relating to the use of newly formulated vaccines for emergency use, some of which will contain new adjuvants, or compounds that allow immunization doses to be diluted, giving more people access to the shots.

Pregnancy

Pregnant women are at special risk for influenza infection based on morbidity and mortality from previous pandemics and from intense flu seasons, the report said.

The committee reviewed the use of inactivated seasonal flu vaccine in 2003 and concluded that the risk-benefit of immunization during all stages of pregnancy should be reconsidered, given the high risk to the mother and fetus of the disease itself, and the likely small risk to mother and fetus of the inactivated flu vaccine, the report said.

It said there are no data on the safety profile of candidate pandemic flu vaccines when administered during pregnancy and reproductive toxicity studies using animal models should be conducted.



To contact the reporter on this story:
Jason Gale in Singapore at j.gale@bloomberg.net

Last Updated: July 15, 2006 01:13 EDT

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