Prevalence of malaria infection in pregnant women compared with children for tracking malaria transmission in sub-Saharan Africa: a systematic review and meta-analysis.

Anna M Van Eijk,Robert W Snow,Jenny Hill,Abdisalan M Noor,Feiko O Ter Kuile

doi:10.1016/s2214-109x(15)00049-2

Abstract

SummaryBackgroundIn malarious areas, pregnant women are more likely to have detectable malaria than are their non-pregnant peers, and the excess risk of infection varies with gravidity. Pregnant women attending antenatal clinic for their first visit are a potential pragmatic sentinel group to track the intensity of malaria transmission; however, the relation between malaria prevalence in children, a standard measure to estimate malaria endemicity, and pregnant women has never been compared.MethodsWe obtained data on malaria prevalence in pregnancy from the Malaria in Pregnancy Library (January, 2015) and data for children (0–59 months) were obtained from recently published work on parasite prevalence in Africa and the Malaria in Pregnancy Library. We used random effects meta-analysis to obtain a pooled prevalence ratio (PPR) of malaria in children versus pregnant women (during pregnancy, not at delivery) and by gravidity, and we used meta-regression to assess factors affecting the prevalence ratio.FindingsWe used data from 18 sources that included 57 data points. There was a strong linear relation between the prevalence of malaria infection in pregnant women and children (r=0·87, p<0·0001). Prevalence was higher in children when compared with all gravidae (PPR=1·44, 95% CI 1·29–1·62; I2=80%, 57 studies), and against multigravidae (1·94, 1·68–2·24; I2=80%, 7 studies), and marginally higher against primigravidae (1·16, 1·05–1·29; I2=48%, 8 studies). PPR was higher in areas of higher transmission.InterpretationMalaria prevalence in pregnant women is strongly correlated with prevalence data in children obtained from household surveys, and could provide a pragmatic adjunct to survey strategies to track trends in malaria transmission in Africa.FundingThe Malaria in Pregnancy Consortium, which is funded through a grant from the Bill & Melinda Gates Foundation to the Liverpool School of Tropical Medicine, UK; US Centers for Disease Control and Prevention; and Wellcome Trust, UK.

Highlights

In malaria transmission areas, pregnant women—in particular primigravidae—are known to be susceptible to malaria and to have higher prevalence and densities of parasitaemia than are non-pregnant women from the same population.[1]
The size of the excess risk varies with the age of the pregnant woman, reflecting cumulative exposure to malaria over a lifetime, and with parity, as a result of pregnancy-specific immunity acquired after exposure to malaria in previous pregnancies
The contemporaneous prevalence data in children and pregnant women were either extracted from studies reported in the Malaria in Pregnancy Library that reported data in children, or obtained from surveys that collected data on pregnant women and children simultaneously. We identified these data from the large database of over 28 483 temporally and spatially unique surveys of malaria infection undertaken across Africa since 1980 and described elsewhere,[6] and from nationally representative household surveys, such as Demographic and Health Surveys, Multiple Indicator Cluster Surveys, and Malaria Indicator Surveys.[13,14,15]

Summary

Introduction

Pregnant women—in particular primigravidae—are known to be susceptible to malaria and to have higher prevalence and densities of parasitaemia than are non-pregnant women from the same population.[1] The size of the excess risk varies with the age of the pregnant woman, reflecting cumulative exposure to malaria over a lifetime, and with parity, as a result of pregnancy-specific immunity acquired after exposure to malaria in previous pregnancies. The World Health Organization recommends use of insecticide-treated nets (ITNs) and intermittent preventive treatment in pregnancy (IPTp) with a dose of sulfadoxine-pyrimethamine at every scheduled antenatal care visit for the prevention of malaria in pregnancy in areas with moderate-to-high malaria transmission.[2,3,4] because of rising parasite resistance to sulfadoxine-pyrimethamine and decreasing malaria transmission in some regions, alternative strategies for IPTp are being assessed, such as screening and treatment strategies in pregnancy. This approach consists of the use of rapid diagnostic tests to screen women for malaria at the first or each antenatal visit and treatment of positive women with artemisinin combination therapies.[5]

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