Influenza pandemics occur on an average of every 30 years. When there is a new flu virus that is genetically different enough that humans have not acquired antibodies for it previously, and that is highly contagious as well as pathogenic for humans, a pandemic is likely. Flu vaccines are limited by production methods. Individuals and families can prepare for prolonged closures of schools and businesses and support other commonsense measures.
There are Many Types and Subtypes of Flu Viruses
Until 2009, the most common flu virus circulating among people has been the Hong Kong Flu, or H3N2. It infected 30 million Americans and killed 34,000 between 1968 and 1969, during the last major pandemic. For the past ten years, researchers have feared the bird, or avian, flu would become a global pandemic but so far this particularly deadly form has not mutated to become highly contagious.
Asian flu (H2N2) infected approximately one-third of the world's population in 1957 and 1958, but death rates were lower than expected. The Spanish flu of 1918 was the killer of 100 million people, according to an article in the January 2006 Journal of Emerging Infectious Diseases, 20 times the rate of expected flu deaths in that era. Spanish flu was an H1N1 virus, but was a much more lethal form.
If the term "swine flu" (H1N1) is familiar, however, it is because of the death of one Fort Dix soldier in New Jersey and 13 others who became ill with it in 1976. Center for Disease Control (CDC) scientists feared it was a return of the Spanish flu, which was thought to have originated in pigs, and started a campaign of widespread vaccination. After a few victims of the vaccine developed Guillain-Barre' syndrome, a rare paralytic disorder, vaccines were stopped.
The current H1N1 combines the genetics of Eurasia strains with those from the Americas. Such a combination has never before been detected. The New Jersey strain was not as capable of person-to-person transmission as the current version. 99% of circulating influenza virus in the United States is now thought to be H1N1.
The overwhelming majority of those who contract the H1N1 flu experience only mild illness. There are no signs that the virus has mutated to a more virulent form that would cause more deaths than previous flu seasons. The Spanish flu of 1918 came in phases, the first being a mild illness in spring or summer that took only a few days to recover from, and a return phase during fall and winter that took more lives. Scientists for the Vitamin D Council believe that lowered vitamin D levels during seasons when the sun is more distant make people more susceptible to winter viruses.
Why Flu Vaccines Fall Short
Manufacturers were well into production of Hong Kong flu vaccine when H1N1 began skipping across the globe. Methods of flu and yellow fever vaccine development is 1950s science that has not changed: inoculate fertile eggs laid by hens under hygienic conditions and wait for the virus to grow. Only a limited number of companies in the world produce flu vaccines and the process starts months before the expected flu season begins. H1N1 grows more slowly in its egg medium than H3N2.
Emergency plans that were made in reaction to the threat of avian flu are in place. States that are in financial crisis may have difficulty meeting the needs of overburdened healthcare systems. Families should make arrangements for alternative child care should schools close, or consider if working from home would be possible. A two to four week supply of water, nonperishable foods and other essentials should be stockpiled.
Over the last century, flu viruses have been tracked and categorized by their ability to kill and to be easily transmitted. Vitamin D from sunshine may help immune defenses against the flu. Vaccine technology is outdated and cannot meet current demands. Everyone should prepare for inconveniences related to limiting the spread of the current flu virus.
References:
Taubenberger J., Morens D., "1918 Influenza: the Mother of all Pandemics" Journal of Emerging Infectious Diseases, Jan 2006 (12):1
"Facts and figures about novel H1N1 flu," CDC website, Oct 23, 2009 www.cdc.gov/h1n1flu/facts_figures.htm
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