Change in body temperature from baseline in individual ferrets before and after H3N2 challenge. Core body temperatures were recorded every 10 min, and baseline body temperatures were calculated by averaging measurements from the 3 days prior to challenge. Dark blue, vacH3N2-vaccinated ferrets; light blue, vacH3N1-vaccinated ferrets; red, vacH1N2-vaccinated ferrets; yellow, vacH1N1-vaccinated ferrets; black, vacPBS-vaccinated ferrets.