Better Bird Flu Vaccine Needed As Current Tests Are A Huge Disappointment.

Source: The Standard

The battle for a much-needed bird flu vaccine suffered a setback Friday.

Proving to be only modestly effective, the vaccine produced apparent protection in slightly over half the people who receive two mega-dose shots.

This strikes a very valid worry that not enough is being stocked for the masses, and what is available will only work a little over 50% of the time.

The first US vaccine against bird flu is only modestly effective, producing apparent protection in slightly over half the people who receive two mega-dose shots, initial testing shows. The worrisome findings underscore the urgency of brewing a better vaccine.

The US government signaled that this vaccine had flaws even as it ordered US$162 million (HK$1.26 billion) worth of shots last year to stockpile if bird flu mutated to spread easily from person to person.

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

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.

The results were not surprising, said lead researcher John Treanor of the University of Rochester. Humans had not until recently been exposed to the deadly H5N1 flu strain, and it takes the immune system a while to ramp up to fight unique types.

I have this striking feeling that when this thing hits, it's going to get really bad, really fast. But I sure can sleep at night with the scientists working on a new bird flu vaccine, when they're not sure how the present one works.

So in this first human study, Treanor and colleagues tested whether the H5N1 vaccine would prompt as much antibody protection as do regular winter flu shots.

Vaccine makers Sanofi-Pasteur and Chiron now are adding immune-enhancing compounds, alum and MF59 respectively, to the experimental vaccine in hopes they will spark protection with doses closer to 15 micrograms, thus stretching limited supplies.

Further complicating matters is that this first H5N1 vaccine is outdated, being based on a version of the virus culled in Vietnam in 2004. Scientists now are creating one based on an Indonesian version that emerged last year. They do not know what protection the older vaccine would spur against the newer virus.

I feel much better now, how about you?

Tags: [avian flu], [bird flu vaccine], [vaccine setback], [H5N1], [vaccine sparked a protective immune response in disappointingly few people], [Vietnam version], [Indonesian version]