(S (S (BASENP (DT The) (NNP WHO)) (VP (ADVP (RB also)) (VP (VBD stated) (SBAR (IN that) (S (BASENP (DT this) (NN phenomenon)) (VP (VP (VBZ does) (RB not)) (VP (VB influence) (NP (BASENP (DT the) (NN effectiveness)) (PP (IN of) (BASENP (NN flu) (NNS immunizations))))))))))) (PERIOD .))