Asia Society held a video conference on November 1, 2005 of a discussion on Avian Flu with the Honorable Michael Leavitt, Secretary, United States Department of Health and Human Services. Dr. Ian Lipkin of the Mailman School of Public Health at Columbia Univeristy presided.
Information on Avian Influenza: H5N1
A Brief Overview of the Current Situation
The H5N1 avian influenza strain, which has killed millions of domestic birds and 53 known humans in the last few years, is on the tipping point of infecting millions world-wide, capable of unleashing a pandemic that could equal or greatly surpass the Spanish Flu of 1918. Of the 20-100 million people worldwide that died in 1918, the most victimized demographic was 10-35 year olds. Unlike the seasonal influenza strains that inflect millions every year and present a serious threat only to children and the elderly, a severe strain of influenza like H5N1 would not simply attack the weak. No human has immunity built up against H5N1; if it undergoes antigenic shift with a human influenza virus, the disease that has a 100% death rate in chickens would (even in a mild pandemic situation) wreak havoc on global health, the global economy, and global security.
All signs point to an H5N1 pandemic, including an increased virulence of the strain in recent samples and the infection and deaths of migratory birds that traditionally carry the virus but show no symptoms. The primary question that remains is not if the pandemic will occur, but when.
The Additional Risks for China and the Asia-Pacific Region
Outbreak is an especially high risk in China; as the Chinese GDP has grown, more people can now afford to eat chicken. This has caused chicken farming to become an enormous industry in China, an industry upon which over a billion people rely for food. Asian consumer practices also do not bode well for an avian-spread disease, specifically the preference to buy live chickens at large outdoor (and often unsanitary) markets for slaughter at home.
Treatment: Vaccine Production
The optimal treatment for H5N1 is unknown; the WHO has recommended that countries stockpile Oseltamivir (produced by the Roche pharmaceutical company under the name Tamiflu). While Tamiflu was shown to be helpful in combating the virus in certain cases, its success has by no means been universal. There are very few pharmaceutical companies interested in producing vaccines – financially, vaccines are a risky investment for a variety of reasons. Flu vaccines currently comprise 2% of the global pharmaceutical market. Because of the seasonal nature of the virus, flu vaccines must be made rapidly (which subsequently increases the risk of both contamination and error). Each year the WHO participates in vaccine development by deciding every February which particular strains will be most prominent in the upcoming season. Given the time it takes to produce vaccines (and the fact that only nine countries have the capabilities, with only a handful of willing pharmaceutical companies interested), it is not until September or October that the vaccines are available, usually just in time for the start of the North American flu season. Because the Asian flu season typically begins in the early summer, there is no way to get vaccines to Asia in time. And even if there were a way, there is still the issue of quantity.
Currently, annual production of influenza vaccine is limited to about 300 million trivalent doses. To counter a new strain of pandemic influenza that has never circulated throughout the population, each person would most likely need two doses for adequate protection. In a best-case scenario, less than 500 million people (14% of the world’s population) would be vaccinated within one year of the pandemic’s outbreak. That timetable does not factor in the six additional months that are required to develop the vaccine before mass production can commence.