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Influenza vaccine distribution and B lineage virus circulation in the US Influenza Vaccine Effectiveness (Flu VE) Network. A, Distribution of IIV3 and IIV4 during the 2011–2012 to 2016–17 seasons. B, Influenza B lineage circulation in the US Flu VE network during the 2011–2012 to 2016–2017 seasons. Abbreviations: IIV3, trivalent inactivated influenza vaccine; IIV4, quadrivalent inactivated influenza vaccine.
