The results of a government-funded study show that very high doses of an avian influenza vaccine, supplied by Sanofi-Aventis, are needed to produce an immune response that should guard against the virus. 54% of the volunteers received two shots of 90 micrograms each, 28 days apart. A typical flu shot is 15 micrograms.
Based on the requirements seen in the study, the U.S. government's current stockpile of vaccines would provide enough for only about four million people, according to Dr. Anthony Fauci, director of the National Institute of Allergy & Infectious Diseases.
The problem isn't just a matter of dosage. It is also a matter of production. Flu vaccines are produced using hen's eggs,a 50-year old technology, if it can be called that. Automated machines inject hundreds of thousands of eggs, then an 11-day waiting period begins while the eggs incubate, brewing viruses that are then killed and bottled. To produce millions of the the final product takes about six months.
Then there's the question no one seems to be asking: if we plan to rely upon chicken eggs to incubate an H5N1 virus, how do we know the H5N1 virus won't kill the eggs? H5N1 already kills chickens. Shouldn't we assume it also kills a high percentage of chicken eggs? Sanofi-Aventis is spending $150 million of its own money building a new vaccine-making plant based on the theory that H5N1 won't kill the eggs. By the way, eggs have to be ordered many months in advance for this antiquated process.
And where does Sanofi-Aventis plan to get all these egg-laying chickens anyway? Millions of chickens have been slaughtered worldwide already and a pre-pandemic scenario could kill off whole U.S. chicken farms at once.
However, there is a new vaccine technology on the horizon. It's called cell-based vaccine. Giant vats of living cells, such as dog kidney cells, multiply and then are inoculated with the virus. There are two companies already in the marketplace, one in Holland, one in Germany, but the technology won't be widely available for years. The FDA must review the entire method before any equipment can be imported to the U.S.
Clearly, the U.S. has waited for a new virus to come along to spur vaccine research. We may have waited too long. H5N1 isn't waiting. It's figuring out how to mutate into human-to-human transmission. In fact, the rate of mutation is alarming. Dr. Robert Webster, Ph.D., Member, St. Jude Faculty Rose Marie Thomas Chair, calls H5N1 "the most frightening virus I've ever seen in 40 years of research."
If you and your family are counting on a vaccine to protect you against H5N1 (Avian Influenza), don't bet on it. There are still too many unanswered questions and too many risks. |
