The impact of prenatal exposure to parasitic infections and to anthelminthic treatment on antibody responses to routine immunisations given in infancy: Secondary analysis of a randomised controlled trial.
Chronic parasitic infections are associated with active immunomodulation which may include by-stander effects on unrelated antigens. It has been suggested that pre-natal exposure to parasitic infections in the mother impacts immunological development in the fetus and hence the offspring's response to vaccines, and that control of parasitic infection among pregnant women will therefore be beneficial.



We used new data from the Entebbe Mother and Baby Study, a trial of anthelminthic treatment during pregnancy conducted in Uganda, to further investigate this hypothesis. 2705 mothers were investigated for parasitic infections and then randomised to albendazole (400mg) versus placebo and praziquantel (40mg/kg) during pregnancy in a factorial design. All mothers received sulfadoxine/pyrimethamine for presumptive treatment of malaria. Offspring received Expanded Programme on Immunisation vaccines at birth, six, 10 and 14 weeks. New data on antibody levels to diphtheria toxin, three pertussis antigens, Haemophilus influenzae type B (HiB) and Hepatitis B, measured at one year (April 2004 -May 2007) from 1379 infants were analysed for this report. Additional observational analyses relating maternal infections to infant vaccine responses were also conducted. Helminth infections were highly prevalent amongst mothers (hookworm 43.1%, Mansonella 20.9%, Schistosoma mansoni 17.3%, Strongyloides 11.7%, Trichuris 8.1%) and 9.4% had malaria at enrolment. In the trial analysis we found no overall effect of either anthelminthic intervention on the measured infant vaccine responses. In observational analyses, no species was associated with suppressed responses. Strongyloidiasis was associated with enhanced responses to pertussis toxin, HiB and Hep B vaccine antigens.



Our results do not support the hypothesis that routine anthelminthic treatment during pregnancy has a benefit for the infant's vaccine response, or that maternal helminth infection has a net suppressive effect on the offspring's response to vaccines.



ISRCTN.com ISRCTN32849447.
London School of Hygiene & Tropical Medicine, London, United Kingdom.
Stephen
0000-0003-2086-1740
S
Nash
Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.|The Jenner Institute, University of Oxford, Oxford, United Kingdom.
Alexander J
AJ
Mentzer
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Swaib A
SA
Lule
MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Dennison
D
Kizito
Netherlands National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Gaby
G
Smits
Netherlands National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
Fiona R M
FR
van der Klis
London School of Hygiene & Tropical Medicine, London, United Kingdom.|MRC/UVRI Uganda Research Unit on AIDS, Entebbe, Uganda.
Alison M
AM
Elliott
D000328:Adult; D015766:Albendazole / Q000008:administration & dosage; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage; D000909:Antibodies, Helminth / Q000276:immunology*; D000917:Antibody Formation; D005260:Female; D006373:Helminthiasis / Q000188:drug therapy / Q000196:embryology / Q000453:epidemiology / Q000276:immunology*; D006376:Helminths / Q000235:genetics / Q000276:immunology; D006801:Humans; D007114:Immunization; D007223:Infant; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000276:immunology* / Q000517:prevention & control; D008297:Male; D011223:Praziquantel / Q000008:administration & dosage; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology*; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D014454:Uganda / Q000453:epidemiology; D014612:Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D055815:Young Adult
D000871:Anthelmintics; D000909:Antibodies, Helminth; D014612:Vaccines; D011223:Praziquantel; D015766:Albendazole