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Effect of probiotics on vaccine antibody responses in infancy – a randomized placebo-controlled double-blind trial


Dr Kaarina Kukkonen, Helsinki University Central Hospital, the Skin and Allergy Hospital, Meilahdentie 2, PO Box 160, 00029 HUS Helsinki, Finland
Tel.: +358 44 324 9388, +358 9 471 86353
Fax: +358 9 471 86416


Probiotics are immunomodulatory and may thus affect vaccine antibody responses. With the accumulating evidence of their health-promoting effects, probiotics are increasingly administered in allergy-prone infants. Therefore, we studied the effect of probiotics on antibody responses to diphtheria, tetanus and Haemophilus influenzae type b (Hib) vaccines in 6-month-old infants participating in a randomized placebo-controlled double-blind allergy-prevention trial. Mothers of unborn children at increased risk for atopy used a combination of four probiotic strains, or a placebo, for 4 wk before delivery. During 6 months from birth, their infants received the same probiotics and galacto-oligosaccharides, or a placebo. The infants were immunized with a DTwP (diphtheria, tetanus and whole cell pertussis) at ages 3, 4, and 5 months, and with a Hib polysaccharide conjugate at 4 months. Serum diphtheria, tetanus, and Hib IgG antibodies were measured at 6 months. In the probiotic group, protective Hib antibody concentrations (≥1 μg/ml) occurred more frequently, 16 of 32 (50%) vs. six of 29 (21%) (p = 0.020), and the geometric mean (inter-quartile range) Hib IgG concentration tended to be higher 0.75 (0.15–2.71) μg/ml than in the placebo group 0.40 (0.15–0.92) μg/ml (p = 0.064). In these respective groups, diphtheria, 0.38 (0.14–0.78) vs. 0.47 (0.19–1.40) IU/ml (p = 0.449), and tetanus, 1.01(0.47–1.49) vs. 0.81 (0.56–1.39) IU/ml (p = 0.310), IgG titers were comparable. In conclusion, in allergy-prone infants probiotics seem not to impair antibody responses to diphtheria, tetanus, or Hib, but may improve response to Hib immunization.