Saturday, July 30, 2005
Only one licensed drug appears to be effective in birds carrying the strain.
WASHINGTON POST
WASHINGTON -- Public health officials preparing to battle what they view as an inevitable influenza pandemic say the world lacks the medical weapons to fight the disease effectively and will not have them anytime soon.
Public health specialists and manufacturers are working frantically to develop vaccines, drugs, strategies for quarantining and treating the ill, and plans for international cooperation, but these efforts will take years. Meanwhile, the most dangerous strain of influenza to appear in decades -- the H5N1 "bird flu" in Asia -- is showing up in new populations of birds, and occasionally people, almost by the month, global health officials say.
If the virus were to start spreading in the next year, the world would have only a relative handful of doses of an experimental vaccine to defend against a disease that, history shows, could potentially kill millions. If the vaccine proved effective, and every flu vaccine factory in the world started making it, the first doses would not be ready for four months. By then, the pathogen would probably be on every continent.
Frantic preparations
Theoretically, antiviral drugs could slow an outbreak and buy time. The problem is only one licensed drug, oseltamivir, appears to work against bird flu. At the moment, there is not enough stockpiled for widespread use. Nor is there a plan to deploy the small amount that exists in ways that would have the best chance of slowing the disease.
The public, conditioned to believe in the power of modern medicine, has heard little of how poorly prepared the world is to confront a flu pandemic, which is an epidemic that strikes several continents simultaneously and infects a substantial portion of the population.
Since the current wave of avian flu began sweeping through poultry in Southeast Asia more than 18 months ago, international and U.S. health authorities have warned of the danger and tried to mobilize. Research on vaccines has accelerated, efforts to build drug supplies are under way, and discussions on developing a coordinated global response take place regularly.
The U.S. Department of Health and Human Services will spend $419 million in pandemic planning this year. The National Institutes of Health's influenza research budget has quintupled in the past five years.
"The secretary or the chief of staff -- we have a discussion about flu almost every day," said Bruce Gellin, head of HHS's National Vaccine Program Office. This week, a committee is to deliver to HHS Secretary Mike Leavitt an updated plan for confronting a pandemic.
Fearful scientists
Despite these efforts, the world's lack of readiness to meet the threat is huge, experts say.
"The only reason nobody's concerned the emperor has no clothes is that he hasn't shown up yet," Harvey V. Fineberg, president of the National Academy of Sciences' Institute of Medicine, said recently of the world's efforts to prepare for pandemic flu. "When he appears, people will see he's naked."
Other scientists are sounding the alarm as well.
The most outspoken is Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. In writing and in speeches, Osterholm reminds his audience that after public calamities, the United States usually convenes blue-ribbon commissions to pass judgment. There will be one after a flu pandemic, he believes.
"Right now, the conclusions of that commission would be harsh and sad," he said.
Proposed measures
In hopes of slowing a pandemic's spread, public health specialists have been debating proposals for unprecedented countermeasures. These could include vaccinating only children, who are statistically most likely to spread the contagion; mandatory closing of schools or office buildings; and imposing "snow day" quarantines on infected families -- prohibiting them from leaving their homes.
Other measures would go well beyond conventional boundaries of public health: restricting international travel, closing transit systems or nationalizing supplies of critical medical equipment, such as surgical masks.
Osterholm argues such measures would fall far short. He predicts a pandemic would cause widespread shutdowns of factories, transportation and other essential industries. To prepare, he says, authorities should identify and stockpile a list of perhaps 100 crucial products and resources that are essential to keep society functioning until the pandemic recedes and the survivors go back to work.
Since late 2003, 109 people are known to have been infected with the emerging H5N1 virus in Asia. About half -- 55 -- have died.
Ironically, for the current H5N1 strain of avian flu to gain "pandemic potential," it will have to become less deadly. Declining lethality is a key sign that the microbe is adapting to human hosts. That is one reason the 34 percent mortality observed in the most recent outbreak -- a cluster of cases in northern Vietnam -- worries scientists.
Pandemic influenza is not an unusually bad version of the flu that appears each winter. Those outbreaks are caused by flu viruses that have been circulating for decades and change slightly year to year.
Pandemics are caused by strains of virus that are highly contagious and to which people have no immunity. Such rare strains arise from the chance scrambling and recombination of an animal flu virus and a human one, resulting in a strain whose molecular identity is wholly new.
If H5N1 never becomes easily transmissible in human beings, it will never become a pandemic. If it does become transmissible, the consequences are difficult to imagine. But history provides some clues.
The "Spanish flu" in 1918 and 1919 was the biggest and, along with AIDS, the most important infectious disease outbreak of the 20th century. It is on the short list of great disasters in human history.
At least 50 million people, and possibly as many as 100 million, died when the world's population was 1.9 billion people, one-third its current size.
Vaccine production
As the first, small hedge against disaster, the government last fall ordered 2 million doses of H5N1 vaccine from Sanofi Pasteur, one of the country's three flu vaccine makers, even though nobody yet knows whether it works.
About 300 million flu shots are made worldwide each year. The vaccine protects against three flu strains. If the global production capacity were directed to make only H5N1 vaccine, the output could be 900 million shots.
Unfortunately, virologists are almost certain people will need two doses about a month apart to mount a successful immune response against a wholly new strain such as H5N1. That would cut the theoretical number of recipients worldwide to 450 million. If each shot requires a larger-than-usual amount of vaccine to work, the number will be even smaller.
Can the world produce more flu shots? Not easily.
Because nearly all flu vaccine is made by growing the virus in fertilized chicken eggs, special factories and a steady supply of eggs is required.
Around the world, flu vaccine production has risen by just one-third in the past decade. New plants in Brazil, South Korea and the Netherlands will boost global production by an additional 25 percent in the near future.
In theory, even a modest amount of vaccine might be useful. Fighting disease outbreaks is like fighting fires.