Influenza Vaccine Questions & Answers from the Centers for Disease Control and Prevention (CDC)
2009 - 2010 Influenza Vaccine Strains
Both the inactivated and the live, attenuated influenza vaccine prepared for the 2009-10 season will include:
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an A/Brisbane/59/2007 (H1N1)-like virus;
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an A/Brisbane/10/2007 (H3N2)-like virus;
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a B/Brisbane 60/2008-like virus.
These viruses will be used because they are representative of influenza viruses that are anticipated to circulate in the United States during the 2009-10 influenza season and have favorable growth properties in eggs.
The inactivated influenza vaccine (the "flu shot") is FDA-approved for persons 6 months of age and older, including those with high-risk conditions, whereas the live, attenuated influenza vaccine (the nasal-spray flu vaccine) is FDA-approved for use only among healthy, non-pregnant persons aged 2 to 49 years. All children aged 6 months through 8 years who are receiving flu vaccine for the first time should receive 2 doses of vaccine. Children 6 months through 8 years who received flu vaccine for the first time during the previous influenza season, and got only one dose, should receive 2 doses this season. Children who were given influenza vaccine during any other prior flu season should receive only one dose.