Ricardo Basurto-Davila, PhD, MS¹, Mark Thompson, PhD¹, Nancy Dube, RN, MPH², Sandra Chaves, MD, MSc³, Jill Ferdinands, PhD³, Samuel Graitcer, MD³, Lydia Foster, MS³, Peter Smith, PhD⁴, Amra Uzicanin, MD, MPH, Meredith Tipton, PhD, MPH, Jufu Chen, PhD³, Paul Gargiullo, PhD³, Rebel Jackson, RN, NCSN, MPA¹, Arnold Monto, MD, MPH⁶ and David Shay, MD, MPH¹, 1Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, 2Maine Department of Education, Augusta, ME, 3Centers for Disease Control and Prevention, Atlanta, GA, 4IDEXX Laboratories, Inc, Westbrook, ME, 5University of Michigan, Ann Arbor, MI