A further worrying factor is that while most flu viruses can only replicate inside the lungs, the H5 class are able to replicate almost anywhere in the body. They can therefore overwhelm the host’s immune system far more quickly. To date, Nayak says, there is no evidence that H5N1 has gone through reassortment with any human virus. "This is not like any virus we have seen in human history," he adds. "We should be doing everything we possibly can to prevent human infection."
As with most health issues, it is not just a matter of understanding the science better, but also the economics. One critical strategy to prevent reassortment between human and bird-flu viruses would be to make sure that all poultry-farm workers everywhere are vaccinated against human flu. Indeed, Thai authorities have expressed a desire to do just that, but they have only some 100,000 donated doses of flu vaccine, which is not nearly enough. Ninety-five percent of flu vaccine routinely goes to developed nations, leaving developing countries criminally short.
Moreover, there are very few companies working on new types of vaccines. Most of the techniques currently used to make flu vaccines were developed during World War II. Early next year the National Institute of Allergy and Infectious Diseases will begin conducting clinical trials of an experimental human vaccine against avian influenza, but much more needs to be done. Recently the WHO has warned of the need to speed up R&D. Should a new pandemic arise, the agency has estimated we would likely need 2 billion doses worldwide! The fact that the U.S. is now struggling to produce enough doses of regular flu vaccine should be a cause for extreme concern, says Monto. "If we don’t have the capacity to produce enough for regular flu, then we won’t have the capacity to produce for a pandemic."
Few countries have any significant stockpiles of vaccines on hand — or of antiviral drugs such as Tamiflu that can help to save lives when new strains appear. Although the effectiveness of Tamiflu against avian influenzas has not been rigorously proved, it is the only drug we have at the moment that may be effective. Poor countries like Thailand cannot afford to provide hundreds of thousands of doses of such an expensive commodity — in the U.S. a course of 10 capsules costs $75 and up. In Vietnam, which is poorer still, The New York Timeshas reported that the country’s military has been confiscating foreign donations of Tamiflu for their own use. Monto insists that we cannot let market forces rule here. Somehow the world must begin to take collective responsibility for protecting not just rich nations but also poor ones against this most dangerous enemy.
Bird viruses in Bangkok may seem a distant problem, but in the age of jet travel, novel viruses that arise in one corner of the world can soon spread everywhere. Influenza recognizes no national boundaries; driven by purely mechanical necessity, it will travel by any means possible. This is a foreign agent of which we should be truly afraid.