Impact of Helminth Infections during Pregnancy on Vaccine Immunogenicity in Gabonese Infants.

Judith Flügge,Meral Esen,Selidji Todagbe Agnandji,Mohamed Duali,Ayôla Akim Adegnika,Benjamin Mordmüller,Bertrand Lell,Sina Brückner,Gédéon Prince Manouana,Peter G Kremsner,Marguerite Massinga Loembe,Johannes Strunk,Esther Askani,Yabo Josiane Honkpehedji,Thaisa L Sandri

doi:10.3390/vaccines8030381

Abstract

Helminth infections are common in sub-Saharan Africa. Besides direct clinical effects, a bias towards a T helper type 2 (Th2) cell immune response is observed. The consequences of parasite infection during pregnancy for the mother and particularly for the fetus and the newborn can be severe and may include impaired immune response during acute infection and vaccination. Here, we present data of immune responses to vaccines given within the expanded program on immunization (EPI) of infants born to helminth infected or non-infected mothers. The study was conducted in Lambaréné and surroundings, Gabon. Maternal helminth infection was diagnosed microscopically using the Kato-Katz method for soil-transmitted helminths (STH), urine filtration for Schistosoma haematobium infections and the saponin-based method for filarial infections. Plasma antibody levels to different vaccine antigens were measured in mothers and their offspring by enzyme-linked immunosorbent assay (ELISA) at different timepoints. We found 42.3% of the mothers to be infected with at least one helminth species. Significantly lower anti-tetanus toxoid immunoglobulin (Ig) G was detected in the cord blood of infants born to helminth infected mothers. Following vaccination, immune responses of the infants to EPI vaccines were similar between the two groups at nine and 12 months. Even though infection with helminths is still common in pregnant women in Gabon, in our setting, there was no evidence seen for a substantial effect on infants’ immune responses to vaccines given as part of the EPI.

Highlights

Through the implementation of vaccination programs like the expanded program of immunization (EPI), infants worldwide receive very similar vaccination schemes
The assessment of parasite infection showed that 42.3% (52/123) of the enrolled mothers were helminth positive
T. trichiura was found in 13.5% (7/52), hookworm in 7.7% (4 in 52), and

Summary

Introduction

Through the implementation of vaccination programs like the expanded program of immunization (EPI), infants worldwide receive very similar vaccination schemes. There are tremendous discrepancies within and between different regions regarding vaccine efficacy with several studies reporting that children in low- and middle-income countries are less responsive to vaccines than children from high-income countries [1,2,3,4,5,6,7,8] This is presumably associated with malnutrition and infections, in particular with parasites [9,10,11,12]. Helminth infection affects more than two billion people worldwide [13,14] and is highly prevalent in sub-Saharan Africa It is considered as a major public health problem but remains neglected because helminths mostly affect underprivileged populations of low- and middle-income countries. Nguema et al examined the prevalence of soil-transmitted helminths (STH) and schistosomiasis among schoolchildren of the Northern and Eastern Health regions of Gabon [21] and Veletzky et al found a prevalence of 50.8% of the filarial parasite Loa loa among the 1232 participants from the Gabonese departments of Tsamba-Magotsi and Ogooué et des Lacs [22]

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