Age distribution of contact subjects with laboratory-confirmed A(H1N1)pdm09 infection, Kamphaeng Phet, Thailand.

aNumber in parenthesis refers to sample determined to be positive by qRT-PCR without documented seroconversion or single positive HI titer. bSymptomatic infections include those having positive respiratory sample for A(H1N1)pdm09 by qRT-PCR or ≥4-fold increase in HI titer of paired ILI sera or single positive HI titer with ILI or respiratory illness within 7 days prior to study enrollment. cSubclinical infections include those having ≥4-fold increase in HI titer of paired ILI sera or single positive HI titer without ILI or respiratory illness within 7 days prior to study enrollment. Age distribution of contact subjects with laboratory-confirmed A(H1N1)pdm09 infection, Kamphaeng Phet, Thailand.