The stockpiling of antiviral drugs, making more flu vaccine and better surveillance for new flu strains were among the suggestions mentioned in a long-awaited draft document, released yesterday by the Department of Health and Human Services, on how the United States can get ready for pandemic flu.
"What we're trying to do from a preparedness perspective is to say this is real, this is serious, and that the time to be complacent about flu is over," said Julie L. Gerberding, director of the Centers for Disease Control and Prevention.
"This is an opportunity to begin to educate the public about what a pandemic is, and what will be necessary to respond to one," said Bruce Gellin, director of HHS's National Vaccine Program and a main author of the 56-page document.
First called for in 1993, the "Pandemic Influenza Preparedness and Response Plan" poses nearly as many questions as it provides answers. HHS is seeking comment from state and local health departments, as well as the medical community and the public, over the next two months before coming up with a final plan.
"Pandemic" influenza refers to a strain of flu virus that is new and capable of being easily transmitted in human populations. The flu virus that circulates each winter in nearly all cases is a genetic variation of a microbe already in circulation. Slightly new strains come and go year to year, some more transmissible or deadly than others.
Periodically, however, there is a chance fusion and "recombination" of a human flu virus and a flu virus carried by birds or pigs. If the resulting microbe has the ability to be easily passed person to person -- and most hybrids do not -- then it can potentially infect the entire globe, as nobody has immunity to it (or a closely related strain) from past infections.
Such a pandemic occurred in 1918 and 1919 with the "Spanish flu," which killed about 50 million people.
There were less severe pandemics in 1957 and 1968. Epidemiologists and virologists believe it is only a matter of time before a new pandemic strain emerges. The H5N1 avian flu virus that killed millions of birds -- and several people -- in East Asia last winter is a candidate, should it become able to be easily transmitted among humans.
Experts estimate pandemic influenza might kill between 89,000 and 207,000 people in the United States. Annual influenza mortality is between 20,000 and 40,000.
Many of the actions proposed are underway. Scientists are producing a small amount of vaccine from a "seed virus" made from the H5N1 flu strain now circulating in Asia. When that work is finished in November, the vaccine will be tested in a small clinical trial in people while a larger batch -- perhaps 2 million doses -- of vaccine is made to see how the strain performs in industrial-scale production.
The federal government is also seeking to buy more oseltamivir -- a drug sold as Tamiflu -- from Roche, the company that is its sole manufacturer. Taken for five days, the drug can prevent infection in people exposed to influenza in many cases. There is enough oseltamivir in the government's "strategic national stockpile" of epidemic and bioterrorism drugs to treat about 1 million people. Gerberding said "we would like to have closer to 100 million" treatments but that production bottlenecks make that impossible at the moment.
A major problem is that it takes six months to make large amounts of flu vaccine, which is grown in fertilized chicken eggs. That is too long a delay to stop a rapidly moving virus. Efforts are underway to find alternative methods using cell cultures. That is unlikely to make the process faster, but it may make it easier to rapidly expand the size of production runs, Gellin said.
Anthony S. Fauci, head of the National Institute for Allergy and Infectious Diseases, said "there is really a full-court press going on now to develop" flu vaccines that protect against many strains of the virus, not simply a single strain and its very close relatives, as is now the case.
HHS wants to hear from health departments and the public about who should get vaccines or antiviral drugs if supplies are short. The plan names a number of scenarios, including ones that target the most at risk of death (such as the ill or elderly), the most at risk of infecting others (such as health care workers), or people whose jobs are important (such as police and fire personnel).
The plan says it may be necessary to screen travelers, close schools and quarantine mildly ill people to limit spread of the disease. It noted, however, that given the nature of flu -- which is transmitted much more easily than the virus that causes severe acute respiratory syndrome, which caused a global response last year -- even that might not slow a pandemic much.