December 05, 2003
Future Natural Influenza Strain Mutations Seen As Great Threat

Writing in the journal Science influenza experts Richard Webby and Robert Webster see the inevitable rise of a future mutant strain of influenza that could kill millions of people.

Nature's "on-going experiments" with influenza strains "may be the greatest bio-terror threat of all", with the world alarmingly unprepared for a global epidemic, researchers warn today.

Another pandemic of the kind that killed up to 40 million people worldwide in 1918 is inevitable - and could be imminent, according to a team from St Jude Children's Research Hospital in Memphis.

Current methods for manufacturing flu vaccines take too much time.

Using current technologies, it takes as long as six months to create flu vaccines.

"The world will be in deep trouble if the impending influenza pandemic strikes this week, this month, or even this year," write international flu experts Richard Webby and Robert Webster of in Memphis.

Techniques that promise to accelerate flu vaccine manufacture ought to be tested and facilities scaled up to be ready for emergency use.

The technology exists to make a flu vaccine more accurately and much more quickly through a technique called reverse genetics, but the method is not yet approved for use in humans. The current method uses chicken eggs as a sort of incubator for viral genes, a process that involves both guesswork and time. Reverse genetics relies less on both of these factors.

"The advantages of reverse genetics is that we can do it much more quickly and have exactly what we need," Webster said, sometimes in as little as two or three weeks. Clinical trials are needed, he added.

Two families of drugs are now available for the flu, amantadine and neuraminidase inhibitors (like Tamiflu and Relenza). Existing supplies could be wiped out in days, however, Webster cautioned. "It would take about 18 months to start from primary chemicals to make more antivirals," he said.

Vaccine production facilities are not large enough to rapidly make vaccines in response to an acute emergency.

“If an influenza pandemic started tomorrow, we would not be able to head it off with vaccines because the production facilities available to produce them are grossly inadequate,” said Robert G. Webster, Ph.D., a member of the Infectious Diseases department and holder of the Rose Marie Thomas Chair at St. Jude. Webster is co-author of the Science article.

This ability to rapidly make hundreds of millions of vaccine shots is a capability that the industrialized nations ought to develop. It would be useful in an emergency in response to natural and man-made pathogen pandemics. There is also the problem of how to rapidly identify which antigens a DNA vaccine or other type of vaccine should code for. In the case of influenza outbreaks that usually can be done fairly rapidly. But for other pathogens the job can be much tougher (even taking many years) and therefore there is a need for the development of biotechnologies that could accelerate the process identifying the most promising antigens to use in a vaccine.

As for the antiviral drugs: the efficacy of existing antivirals that are used against influenza are of such limited efficacy that the FDA is criticised in some quarters for approving them for sale. When a real killer influenza pops up the ability to very rapidly develop and manufacture a vaccine will likely be of far greater benefit than the antiviral drugs. But if a killer influenza pops up what would really help the most is probably the rapid implementation of rules and the propagation of sound advice that will reduce the risk of transmission. It would help to do more research ahead of time to identify the least disruptive techniques for reducing the rate of transmission of influenza. What would be the relative value of face masks, closure of schools, avoidance touching of handrails or door knobs, and other changes to daily routines? That would be great to know.

Share |      Randall Parker, 2003 December 05 01:07 AM  Dangers Natural Bio


Comments
eric bloodaxe said at December 7, 2003 9:43 AM:

Adamantine surely

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