(S (S (BASENP (DT The) (NN vaccine)) (VP (VBD was) (VP (VP (VP (VP (VBN tested) (PP (IN on) (NP (BASENP (NN 400) (NNS Australians)) (VP (VBN aged) (PP (IN between) (BASENP (NN 18) (CC and) (NN 45))))))) (PP (IN in) (BASENP (NNP October)))) (BASENP (JJ last) (NN year))) (S (VP (TO to) (VP (VB determine) (BASENP (PRPD its) (NN safety) (CC and) (NN effectiveness)))))))) (PERIOD .))