Effect of a traditional Chinese medicine, maobushisaishinto, on the antibody titer after influenza vaccination: A randomized, placebo-controlled, double-blind trial

Background: It was shown that a traditional Chinese medicine, maobushisaishinto (MBST), had adjuvant effects on influenza vaccination in an animal experiment and an open trial in elderly subjects. Purpose: To examine the adjuvant effects of MBST in a closer clinical experiment. Methods: Forty-seven healthy subjects between 20 and 71 y of age were randomly assigned to two groups (control and MBST groups) in a double-blind manner. The subjects in the MBST group (n=23) took 1.68g spray-dried powder of MBST/day for two weeks; the rest (control subjects, n=24) took the same amount of indistinguishable placebo. Then subjects were vaccinated against influenza viruses (A/H1N1, A/H3N2 and B). Serum hemagglutination inhibition titers were measured at weeks 0, 1, 2, 4, and 12. Results: The titers against the three viruses were increased continuously for the first two weeks and leveled off. However, MBST was not superior to placebo in any titers. Conclusion: We could not find any adjuvant effects of MBST in this experimental condition.