Helminth infections are a major public health problem, especially in the tropics. Infected individuals have an altered immune response with evidence that antibody response to vaccination is impaired. Hence, treatment of helminth infections before vaccination may be a simple intervention to improve vaccine immunogenicity. In the present study we investigated whether a single-dose antihelminthic treatment influences antibody responses to a seasonal influenza vaccine in primary school children living in Gabon, Central Africa.
In this placebo-controlled double-blind trial conducted in Gabon the effect of a single-dose antihelminthic treatment with 400 mg albendazole versus a placebo one month prior to immunization with a seasonal influenza vaccine was investigated. Antiviral antibody titers against all three vaccine strains were assessed by haemagglutination inhibition (HI) test at baseline (Day 0; vaccination) and four weeks (Day 28) as well as 12 weeks (Day 84) following vaccination. Vaccine-specific memory B-cell response was measured at Day 0 and Day 84 by vaccine-specific Enzyme-linked Immunospot (ELISpot) assay. The trial is registered with the Pan African Clinical Trials Registry (PACTR) (PACTR201303000434188).
98 school children aged 6–10 years were randomly allocated to receive either antihelminthic treatment or placebo and were vaccinated one month after the treatment. The prevalence of helminths at baseline was 21%. Vaccine-specific HI titers against at least one of the three vaccine strains increased at Day 28 and Day 84 in all participants. HI titers against both influenza A strains as well as memory B-cell response were modestly higher in the antihelminthic treated group compared to the placebo group but the difference was not statistically significant. Total but not specific IgA was elevated in the antihelminthic treated group compared to the control group at Day 28.
In our setting antihelminthic treatment had no significant effect on influenza vaccine immunogenicity. A trend towards better antiviral and vaccine immunogenicity in the antihelminthic treated group encourages studies to be conducted with alternative treatment schedules or in populations with a higher helminth burden.
Helminth infections are a major health problem in the tropics and most affected are children. The parasites are able to influence the immune system from a T-helper 1 type response to a T-helper 2 type response. There is evidence that in infected individuals the immune response following vaccination is impaired. Thus pre-treatment with a single-dose of an antihelminthic treatment before vaccination could be a simple and cost-effective intervention to improve vaccine efficacy. In the present study we investigated whether a single-dose antihelminthic treatment with albendazole influences the vaccine outcome to a seasonal influenza vaccine in primary school children living in Gabon, Central Africa. We observed a trend towards a higher anti-viral antibody titer after vaccination in the pre-treated group compared to the placebo control group, albeit not statistical significant. Furthermore we detected a higher concentration of total IgA but not of vaccine-specific IgA. In conclusion, our findings show subtle effects of antihelminthic pre-treatment but are not conclusive enough to recommend a single-dose of albendazole before vaccination to improve vaccine immunogenicity but encourage to conduct further studies in endemic areas with other treatment regiments.