NIH scientists consider fate of pandemic H1N1 flu virus
Scientists are reviewing previous pandemic influenza viruses in the years following a pandemic to better understand future courses for the 2009 pandemic H1N1 (pH1N1) virus during the upcoming flu season and beyond.
Balintfy: Scientist estimate that at least 183 million Americans—that's about 59 percent of the total U.S. population—have some immunity to the 2009 pandemic H1N1 flu virus. Dr. Anthony Fauci, Director at the National Institute of Allergy and Infectious Diseases explains, this is because they were exposed to related viruses or vaccines prior to 2009, were immunized against the virus, or developed immunity following infection with the virus.
Fauci: One of the things people wonder now, as we come through next cycle the year after, what is going to happen with H1N1? Is it going to come back in the pandemic form? Is it going to change? Is it going to completely disappear? Or is it going to assume the recycling that we’ve seen historically that some pandemic viruses do?
Balintfy: To stay in circulation in the face of such high levels of population immunity, the virus must adapt either through abrupt or gradual changes.
Fauci: It is unlikely that H1N1 will return in a pandemic form unless it actually drifts and changes. So, that, in many respects, is good news.
Balintfy: But Dr. Fauci cautions against complacency. He explains that many gaps remain in understanding how a given pandemic flu virus adapts to increased immunity in humans. For that reason, flu vaccination for everyone older than six months is a wise public health measure to maintain high levels of population-wide immunity.
Fauci: Well, that's the overwhelming message. In fact, we’re seeing that there is now some data that’s getting stronger and stronger that prior exposures to various influenzas and prior vaccination to various influenzas does protect you to some extent against the emergence of new strains of influenza, even though they're different from the ones that you were infected with or vaccinated with. So, the new recommendation from the CDC is, unless you have some contraindication, that everyone from six months of age onward should be vaccinated.
Balintfy: Immunization with 2010-2011 seasonal flu vaccine is particularly urged for babies older than six months, children, teens and young adults as the best way to protect individuals in those potentially more susceptible age groups. And Dr. Fauci adds, that this year’s seasonal flu vaccine will include three virus strains.
Fauci: The 2009 H1N1 pandemic flu is one of the three components of this year's seasonal influenza trivalent vaccine. It’s a 2009 H1N1, a Perth H3N2, and a Brisbane/B, so we have it there. And vaccinations are available right now, so we encourage people, even now, to go and get vaccinated when it becomes available in your community.
Balintfy: Dr. Fauci and colleagues recently commented on the possible fate of the 2009 H1N1 pandemic virus in an online publication. For more information on the commentary and season flu vaccination, visit the website, www.niaid.nih.gov. This is Joe Balintfy, National Institutes of Health, Bethesda, Maryland.