“…Antibody induced in the blood in titer higher than 1: 64 was not protective43. Oil-adjuvant vaccine was shown to evoke antibody that persisted as long as 16 months", but in accordance with the preceding sentence, the protective value of measurable antibody in the blood is of little significance. In another institution, an outbreak of influenza A2 affected children who had been vaccinated with a polyvalent vaccine five months before.…”