John E. McDonough, M.Sc., Ren Yuan, M.D., Ph.D., Masaru Suzuki, M.D., Ph.D., Nazgol Seyednejad, B.Sc., W. Mark Elliott, Ph.D., Pablo G. Sanchez, M.D., Alexander C. Wright, Ph.D., Warren B. Gefter, M.D., Leslie Litzky, M.D., Harvey O. Coxson, Ph.D., Peter D.D., Don D. Sin, M.D., Richard A. Pierce, Ph.D., Jason C. Woods, Ph.D., Annette M. McWilliams, M.D., John R. Mayo, M.D., Stephen C. Lam, M.D., Joel D. Cooper, M.D., and James C. Hogg, M.D., Ph.D.: Small-Airway Emphysema and Obstruction in Chronic Obstructive Pulmonary Disease.Most sufferers had low degrees of immunity to pandemic and seasonal influenza A viruses, as indicated by humoral antibody titers. Pandemic and seasonal influenza A virus attacks were associated with identical patterns of viral shedding and clinical illness. Secondary attack rates were approximately double the rates that we observed in the hand-hygiene intervention band of our controlled trial in 2008.9 One possible explanation because of this difference is that immunity among household contacts was lower both to pandemic H1N1 virus also to seasonal H3N2 virus.