Update on Swine Influenza - April 30, 2009

If you've been reading the newspapers, you have seen many mentions of the term "seed stock" in reference to development of a vaccine to address the emerging influenza A virus subtype H1N1 ("swine influenza") pandemic. What does this term mean?

"Seed stock" refers to the isolate of the virus used to prepare the vaccine. So, it is nothing more than the current swine influenza virus, in sufficient quantity to be reproduced (expanded in quantity) sufficiently to allow production of a vaccine by standard methods. Current estimates are that it would take a minimum of 3 to 4 months to produce enough doses of vaccine to address perhaps 15 to 20% of the world's population.

The issue of whether or not to shift the efforts of vaccine manufacturers to focus upon the current swine flu virus is complicated, as most experts believe that this would pose a real risk to the ability to produce vaccine in preparation for the "normal" upcoming flu season. Which would be worse - lack of a vaccine for the current swine flu outbreak, or lack of a vaccine for the predictable outbreak of flu this coming winter? We do not know the answer. However, if vaccine production resources remain limited, as most believe that they will, this decision will have to be made.

Internet resources for information about swine influenza:

Centers for Disease Control (CDC)
Department of Homeland Security (DHS)
World Health Organization (WHO)
Center for Biosecurity at the University of Pittsburgh Medical Center

Emergency Departments in the U.S. are becoming inundated with persons who are fearful that they may have contracted swine flu, even though these individuals mostly do not meet the criteria for suffering from influenza. To remind everyone of these symptoms, they are an acute febrile (associated with fever) respiratory illness. For the purpose of diagnosing A (H1N1) influenza, fever is defined as a measured temperature of at least 100.4 degrees Fahrenheit. To meet the definition of suffering from flu, a person needs to have recent onset of at least one of the following: runny nose or nasal congestion, sore throat, or cough. Other symptoms may include muscle aching and headache, and sometimes, vomiting and/or diarrhea.

Preview the Annual Meeting of the Wilderness Medical Society, which will be held in Snowmass, Colorado July 24-29, 2009.

Join me from January 24 to February 2, 2010 for an exciting dive and wilderness medicine CME adventure aboard the Nautilus Explorer to Socorro Island, Mexico to benefit the Wilderness Medical Society.

Tags: influenza, swine flu, flu, swine influenza, wilderness medicine, outdoor medicine, healthline