- The Washington Times - Wednesday, March 29, 2006

ASSOCIATED PRESS

The nation’s first vaccine against bird flu is only modestly effective, producing apparent protection in slightly more than half the people who receive two megadose shots, initial testing shows. The worrisome findings underscore the urgency of developing a better vaccine.

The government had signaled that this vaccine had serious flaws even as it ordered $162 million worth of shots last summer to stockpile in the event bird flu mutated to spread easily from person to person.

But results of the first human testing, published yesterday in the New England Journal of Medicine, show the extent of the problem: The vaccine prompted a protective immune response in too few people — 54 percent of those who got two shots, 28 days apart, of the highest dose.

Regular winter flu shots, in contrast, protect 75 percent to 90 percent of young healthy people, the same group that first tested the experimental bird-flu vaccine. The elderly typically fare worse; how they respond to the bird-flu shots still is being analyzed.

The results weren’t too surprising, said lead researcher Dr. John Treanor of the University of Rochester. Humans have never been exposed to the deadly bird-flu strain called H5N1, and it takes the immune system awhile to step up to fight unique types of influenza.

The good news: The vaccine seems safe even at doses 12 times stronger than are used in the regular winter flu shot. The main side effect was injection pain.

Researchers are giving the study’s 451 volunteers a third dose, to determine whether that gives more protection. More promising are other studies that add immune-enhancing chemicals to the shots to boost their power, in the hope that people could be protected with lower doses.

“We have a long way to go,” said Dr. Anthony Fauci, infectious disease chief at the National Institutes of Health, which funded the research.

Indeed, because each shot requires such a high dose, the government’s vaccine stockpile contains enough for just 4 million people, far below its initial goal of 20 million.

The world’s vaccine factories are now making regular flu shots for next winter. They would make only bird-flu vaccine if a pandemic broke out. But at these high doses, the maximum that could be produced would fully immunize just 75 million people — 1.25 percent of the world’s population — half of whom wouldn’t be adequately protected, Mayo Clinic flu specialist Dr. Gregory Poland wrote in an accompanying editorial.

Still, “my impression is we are better off having stockpiled this vaccine than none,” said Dr. William Schaffner of Vanderbilt University, a member of an independent panel that closely monitored the shots’ safety during this first human testing.

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