Tuesday, August 11, 2009

Most Recent Update on the H1N1 Swine Flu From the White House

On Tuesday, August 11, 2009, Dr. Richard Hatchett, White House Medical Preparedness Policy Director, spoke at a conference in Arlington, Virginia about the H1N1 swine flu epidemic. As background, he explained that the H1N1 flu has been in the U.S. for the last 30 years - but that the current strain of H1N1 swine flu is significantly different than previously existing strains. He also described how the U.S. has experienced three prior flu pandemics - the most famous being the 1918 flu epidemic, but with another occurring in 1957 and another in the mid-1960's. What we should learn from these previous flu pandemics, according to Dr. Hatchett, is that such pandemics are inevitably multi-year events with the flu increasing in the fall and spring, diminishing during the summer, and then typically returning the next fall and spring - with this continuing for two or more years. For this reason, he emphasized that the development of a vaccine for the H1N1 swine flu is important even if it is not available when the flu returns in the fall. According to Dr. Hatchett, best estimates are that thus far since the H1N1 swine flu appeared this past April, somewhere between 1.5 to 10 million people in the U.S. have been infected with the swine flu (i.e. significantly more than the actual confirmed cases). He also estimates that thus far there have been 436 deaths thus far in the U.S. Because of the wide variation on estimates of the number of people that have been infected with the swine flu, it is impossible at this point to estimate how virulent the current case of the H1N1 swine flu is in terms of mortality rate. What is exceptional about the current pandemic of the H1N1 swine flu, however, is how 50 percent of cases have been in people between age 5 and 24, with the age 25 to 49 having the next highest rate of cases. Also, 60 percent of the hospitalizations have been of young people in the 5 to 24 age group. This is in contrast with the normal flu where the highest incidence of illness is in the age 4 or younger or age 65 or older age groups. Also, normal strains of the flu infect approximately 5 percent of the population over a flu season. In a little over a month in the spring, however, it is estimated that 10 percent of the population of New York City became infected with the swine flu. Thus it is possible that the H1N1 will eventually affect a signficantly greater portion of the population than the normal flu. Coupled with the fact that the H1N1 swine flu also dramatically affects the young at a greater rate than the normal flu, this raises grave concerns about the eventual impacts of the H1N1 swine flu. Currently, the highest "intensity" of the H1N1 swine flu has been in Argentina and Chile in the southern hemisphere where they are currently in the peak of their flu season (i.e. where it is currently in the middle of their winter). Next in "intensity" have been the experiences thus far of Mexico and Canada. While the United States has a signficantly highest "intensity" of the pandemic thus far than most countries, it still has experienced a mild intensity compared with Argentina, Chile, Mexico and Canada. Thus far the H1N1 swine flu pandemic has hit the western hemisphere the hardest, with the exception of Great Britain which has also been hard hit by the swine flu. In summary, flu pandemics have caused a significant number of deaths and social disruption in the past, and there is no reason to believe that the current H1N1 swine flu pandemic will not have a similar affect as demonstrated by the experience of countries like Argentina in the southern hemisphere currently and by Mexico, Canada, and the U.S. this past spring. If the current H1N1 swine flu pandemic is like past flu pandemics, it will be a multi-year challenge for our society to respond to with the greatest challenge for the U.S. still to come this coming fall and spring flu seasons, and possibly during the flu seasons of the following year as well. What could mitigate the impact of the current H1N1 swine flu pandemic, however, is how quickly we can develop and distribute an effective vaccine.