Humoral and cellular immune responses to split-virion H5N1 influenza vaccine in young and elderly adults. by Leroux-Roels, I, Van der Wielen, M, Kafeja, F, Vandermeulen, C, Lazarus, R, Snape, MD, John, T, Carre, C, Nougarede, N, Pepin, S, Leroux-Roels, G, Hoppenbrouwers, K, Pollard, A, Van Damme, P