The impact of helminths on the response to immunization and on the incidence of infection and disease in childhood in Uganda: design of a randomized,double-blind,placebo-controlled,factorial trial of deworming interventions delivered in pregnancy and early childhood [ISRCTN32849447]
Open accessResearch articleFirst published online February, 2007
The impact of helminths on the response to immunization and on the incidence of infection and disease in childhood in Uganda: design of a randomized,double-blind,placebo-controlled,factorial trial of deworming interventions delivered in pregnancy and early childhood [ISRCTN32849447]
Background Helminths have profound effects on the immune response, allowing long-term
survival of parasites with minimal damage to the host. Some of these effects
“spill-over”, altering responses to non-helminth antigens or allergens. It is
suggested that this may lead to impaired responses to immunizations and infections,
while conferring benefits against inflammatory responses in allergic and autoimmune
disease. These effects might develop in utero, through exposure to
maternal helminth infections, or through direct exposure in later life.
Purpose To determine the effects of helminths and their treatment in pregnancy and in
young children on immunological and disease outcomes in childhood.
Methods The trial has three randomized, double-blind, placebo-controlled
interventions at two times, in two people: a pregnant woman and her child. Pregnant
women are randomized to albendazole or placebo and praziquantel or placebo. At age 15
months their children are randomized to three-monthly albendazole or placebo, to
continue to age five years. The proposed designation for this sequence of
interventions is a 2 × 2(×2) factorial design. Children are immunized with BCG and
against polio, Diphtheria, tetanus, Pertussis,
Haemophilus, hepatitis B and measles. Primary immunological outcomes are
responses to BCG antigens and tetanus toxoid in whole blood cytokine assays and
antibody assays at one, three and five years of age. Primary disease outcomes are
incidence of malaria, pneumonia, diarrhoea, tuberculosis, measles, vertical HIV
transmission, and atopic disease episodes, measured at clinic visits and
twice-monthly home visits. Effects on anaemia, growth and intellectual development
are also assessed.
Conclusion This trial, with a novel design comprising related interventions in pregnant
women and their offspring, is the first to examine effects of helminths and their
treatment in pregnancy and early childhood on immunological, infectious disease and
allergic disease outcomes. The results will enhance understanding of both detrimental
and beneficial effects of helminth infection and inform policy.
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