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- H1N1 flu (swine flu): What's happening now
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H1N1 flu (swine flu): What's happening now
Why was H1N1 flu considered a serious threat in 2009?
Any outbreak of a flu-like illness outside the normal flu season should be taken seriously. If the cause turns out to be a completely new flu virus — as it did in 2009 — virtually everyone is at high risk of infection; you can't be immune unless you've been vaccinated or exposed to the virus before. Also, past experience with new flu viruses has shown that they cause more severe illness and death than do recurring seasonal flu viruses — sometimes, substantially more, as was the case in 1918.
So a red flag appeared in April 2009, when two children from neighboring California counties developed a flu-like illness well after the peak of the flu season. By the time experts at the Centers for Disease Control and Prevention (CDC) determined that the cause was a previously unknown — "novel" — influenza virus, the infection had already spread from its apparent site of origin in southern Mexico to several areas in the United States and Canada. It took only a few weeks to appear on every continent.
Did all the announcements about the 2009 pandemic cause unnecessary public alarm?
That's impossible to know. The effects of the pandemic fortunately fell far short of the worst-case projection that the death toll would be higher than that of the great 1918 pandemic. Research may eventually reveal the relative impact and lead to precise methods of predicting the course of the next flu pandemic.
Also, although the 2009-2010 flu season wasn't catastrophic, in the United States, it lasted nearly twice as long as flu seasons in the previous several years and resulted in four to five times as many children's deaths. Overall, it confirmed the unpredictability of influenza A viruses as they evolve under the ever-changing constraints of host evolution and human civilization.
If I get the seasonal flu shot in the fall, will I be safe from H1N1 flu?
Yes. The seasonal flu shot targets three influenza viruses from previous years' flu epidemics. The targeted viruses change each year, based on recommendations from virologists, immunologists and public health experts. The 2009 H1N1 flu virus is one of the three targets of the 2012-2013 seasonal flu shot.
What else can I do to protect myself, my family and my co-workers?
Besides getting vaccinated, you can:
- Wash your hands with soap and water frequently. Alcohol sanitizers also may be helpful.
- Avoid close contact with anyone who has cold or flu symptoms.
- Stay home if you're ill, and encourage others to do the same.
(2 of 2)
- World Health Organization. WHO recommendations for the post-pandemic period. http://www.who.int/csr/disease/swineflu/notes/briefing_20100810/en/index.html. Accessed Sept. 9, 2010.
- Key facts about influenza (flu) and flu vaccine. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/keyfacts.htm. Accessed Aug. 2, 2010.
- Morens DM, et al. The persistent legacy of the 1918 influenza virus. New England Journal of Medicine. 2009;361:225.
- Zimmer SM, et al. Historical perspective — Emergence of influenza A (H1N1) viruses. New England Journal of medicine. 2010;361:279. http://www.nejm.org/doi/full/10.1056/NEJMra0904322. Accessed Aug. 25, 2010.
- Morens DM, et al. The 2009 H1N1 pandemic influenza virus: What next? mBio. 2010;1:e00211. http://mbio.asm.org/content/1/4/e00211-10.full.html. Accessed Sept. 30, 2010.
- The 2009 H1N1 Pandemic: Summary Highlights, April 2009 — April 2010. http://www.cdc.gov/h1n1flu/cdcresponse.htm. Accessed Sept. 30, 2010.
- Fiore AF, et al. Prevention and control of influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2010. MMWR Early Release. 2010;59:1. http://www.cdc.gov/mmwr/pdf/rr/rr59e0729.pdf. Accessed Aug. 2, 2010.
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