FRIDAY, Nov. 28, 2003 (HealthDayNews) -- It's only a matter of time before another influenza pandemic tears through the world, and the world is just not prepared.
Not only do researchers lack adequate methods for producing effective vaccines quickly, no country on earth is stockpiling drugs for this eventuality, say researchers reporting in the Nov. 28 issue of Science.
"The flu keeps knocking at the door," Robert Webster, co-author of the study, said at a teleconference Wednesday. "We need to be prepared."
Although no one can predict when another pandemic will occur, it is widely believed that one is overdue. And recent, troubling signs have been popping up around the globe.
Influenza viruses are classified into subtypes according to the types of proteins (H and N) on the surface. While there are flu epidemics nearly every year, pandemics only happen when the influenza virus acquires a new protein, to which the general population has no immunity.
This is what happened with the deadly Spanish flu pandemic of 1918. That outbreak sickened half the world's population, killing 22 million of them -- far more than did World War I, which was still going on.
The outbreak ranks as the worst epidemic ever to hit the United States. Horrified cities reported that hundreds of people were dying each day, fueling speculation that the Germans were using the flu as a bioweapon. Some cities cancelled public festivities, others reported dramatic drops in crime, and still more mandated that people wear flu masks in public. When it was over, 500,000 Americans were dead.
Today, the growing number of birds and pigs raised for human food consumption and housed in close quarters serve as "mixing bowls" where influenza viruses trade genes, increasing the likelihood that a novel strain will emerge, experts say. SARS, which was unleashed last year, is believed to have come from human contact with animals.
The experts are particularly worried by recent reports of influenza activity in an increasing number of intermediate hosts like swine and poultry, by the wider range of hosts and by an apparent evolution of viruses.
"A lot of alarm bells are going off," Richard Webby, the other co-author of the Science article, said at the same teleconference.
This year, two different outbreaks of bird flu leaped to humans, killing people each time. These were the H5N1 virus in Hong Kong and the H7N7 in the Netherlands.
"We have seen enough incidence [of transfers of the influenza virus from animal reservoirs to humans] in the past three to four years to make us very alarmed," said Webster, the chairman of the infectious diseases department at St. Jude Children's Research Hospital in Memphis. "The only thing that has stood between us and what could be a catastrophe is that the virus has not learned to transmit human to human."
In the Netherlands, however, the H7N7 virus did make some human-to-human transmissions.
There are two things that would help, Webster and Webby contend: a way to more quickly manufacture vaccines and the stockpiling of existing drugs, but neither is being done.
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.
Webster pushed the case even further. "Influenza can be a bioterrorism agent of the very worst kind, a natural bioterrorist agent and how do we prepare for those things? We stockpile," he said. "Authorities have to think about doing so."
The cost of several billion dollars, Webster added, should not be a deterrent. "Isn't the health of the nation and the world worth a few billion dollars?"
To date, no country has invested in stockpiling these antivirals. "They've talked about it but talking doesn't get you there," Webster said.
Officials from the U.S. Centers for Disease Control and Prevention did not respond to questions.
More information
For more on influenza pandemics, visit the CDC. Find a flu shot through the American Lung Association.
