H1N1 Flu Unlikely to Cause Another Pandemic

Kathleen Blanchard's picture
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The H1N1 flu pandemic is over, and scientists say the virus is unlikely to cause another pandemic. The findings are based on a look at the behavior of past influenza viruses. Researchers say H1N1 could become extinct from immunity that is now present in 59 percent of the population.

A high rate of immunity in the general population is a predictor of whether H1N1 flu could resurface. Currently, scientist estimate over half of the population has some degree of protection against H1N1 flu as the result of vaccine, exposure to the virus, or from exposure to a related virus. Another variable is whether the virus mutates. The 1889 and 1918 flu pandemic recurred explosively, but the likelihood is decreased for pH1N1, in part from high rates of vaccination.

Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID) and his NIAID coauthors, Jeffery Taubenberger and David Morens write, "While human influenza viruses have often surprised us, available evidence leads to the hope that the current pandemic virus will continue to cause low or moderate mortality rates if it does not become extinct.”


H1N1 Flu Could Become Extinct, but Caution Urged

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What is to become of the H1N1 flu virus is based on the last six influenza pandemics that date back 163 years. Though the researchers say the virus may even become extinct, they also recommend caution.

"Past history and current understanding suggest cautious optimism that pH1N1 will eventually adapt to stable circulation via genetic changes resulting in continuing moderate or low mortality rates or possibly even disappear entirely.”

Higher rates of mortality are still possible form H1N1 flu for those under age 50. In an effort to increase immunity in the general population and to protect infants, teens and young adults, the authors recommend immunization with seasonal flu vaccine that contains the H1N1 strain this year.

Past history suggests viruses can continue to cause high rates of mortality in younger individuals, years after the pandemic ends. Based on past flu pandemics, an H1N1 flu explosion is unlikely. However, the researchers say much depends on existing immunity. Over time, H1N1 flu could just disappear.

American Society for Microbiology

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