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Bird Flu Vaccine From Cells Hopeful

Posted on: Saturday, 14 June 2008, 03:00 CDT

The first experimental bird flu vaccine made from lab-grown cells instead of chicken eggs shows promise in blocking the highly lethal virus, scientists report.

The advance is good news not just for preparations in case of a pandemic but also because it offers a way to make shots for seasonal flu much faster. That gives health officials crucial extra time to better match annual shots to the flu strains circulating.

It also would reduce dependence on the antiquated system of using millions of eggs to make flu vaccines and could cut production time roughly in half, to as little as 12 weeks, according to maker Baxter International Inc.

Results of midstage testing of the Baxter vaccine, Celvapan, showed two shots produced an immune response considered strong enough to protect 76 percent of healthy adults from both the H5N1 Vietnam strain it targets and the related Hong Kong strain; it appeared to protect 45 percent from a third, Indonesian strain.

"I think it is a big leap forward," said Dr. Wilbur Chen, a vaccine researcher at the University of Maryland School of Medicine not involved in the study.

Since the first outbreak in Hong Kong in 1997, more than 240 people in Asia, Europe and Africa have died from bird flu, which kills about two-thirds of people infected. Nearly all had close contact with poultry, but scientists worry bird flu could mutate to a form easily spread among people, who have no natural immunity. Many experts believe a pandemic will eventually occur.

On Wednesday, Hong Kong health officials ordered the slaughter of all live poultry in street markets because of one of the largest outbreaks of the virus in birds in years.

The United States has stockpiled 23 million doses of egg-based human bird flu vaccine made by three companies; some European countries also have such stockpiles and are ordering Baxter's cell- based vaccine.

Other human vaccines - a few using cells or genetic engineering but most made from eggs - are being tested in dozens of government and commercial projects. Baxter officials say theirs is the first produced in cells that has been tested in people, and they expect to get a European Union license for Celvapan around year's end.

The results of the company-funded study were reported in today's New England Journal of Medicine.

A total of 275 volunteers in Austria and Singapore got one of four doses. The best results - the 76 percent protection - came from the second-lowest dose.

Source: Augusta Chronicle, The

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