Browsing by Author "Crozier, Sarah"

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    Open Access
    Epstein-Barr virus but not cytomegalovirus is associated with reduced vaccine antibody responses in Gambian infants
    (Public Library of Science, 2010) Holder, Beth; Miles, David J C; Kaye, Steve; Crozier, Sarah; Mohammed, Nuredin Ibrahim; Duah, Nancy O; Roberts, Elishia; Ojuola, Olubukola; Palmero, Melba S; Touray, Ebrima S
    BACKGROUND: Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are persistent herpesviruses that have various immunomodulatory effects on their hosts. Both viruses are usually acquired in infancy in Sub-Saharan Africa, a region where childhood vaccines are less effective than in high income settings. To establish whether there is an association between these two observations, we tested the hypothesis that infection with one or both viruses modulate antibody responses to the T-cell independent meningococcal polysaccharide vaccine and the T-cell dependent measles vaccines. METHODOLOGY/PRINCIPAL FINDINGS: Infection with EBV and CMV was diagnosed by the presence of virus-specific IgM in the peripheral blood or by the presence of IgG at higher levels than that found in umbilical cord blood. Anti-meningococcus IgG and IgM were quantified by ELISA. Anti-measles antibody responses were quantified by haemagglutinin antibody inhibition assay. Infants infected with EBV had reduced IgG and IgM antibody responses to meningococcal polysaccharides and to measles vaccine. Infection with CMV alone predicted no changes in the response to meningococcal polysaccharide. While CMV alone had no discernable effect on the antibody response to measles, the response of infants infected with both CMV and EBV was similar to that of infants infected with neither, suggesting that the effects of CMV infection countered the effects of EBV on measles antibody responses. CONCLUSIONS: The results of this exploratory study indicate that infection with EBV is associated with reduced antibody responses to polysaccharides and to measles vaccine, but suggest that the response to T-cell dependent antigens such as measles haemagglutinin may be restored by infection with CMV.
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    Open Access
    Placental Malaria is associated with reduced early life weight development of affected children independent of low birth weight
    (BioMed Central Ltd, 2010) Walther, Brigitte; Miles, David; Crozier, Sarah; Waight, Pauline; Palmero, Melba; Ojuola, Olubukola; Touray, Ebrima; Sande, Marianne; Whittle, Hilton; Rowland-Jones, Sarah; Flanagan, Katie
    BACKGROUND: Infection with Plasmodium falciparum during pregnancy contributes substantially to the disease burden in both mothers and offspring. Placental malaria may lead to intrauterine growth restriction or preterm delivery resulting in low birth weight (LBW), which, in general, is associated with increased infant morbidity and mortality. However, little is known about the possible direct impact of the specific disease processes occurring in PM on longer term outcomes such as subsequent retarded growth development independent of LBW. METHODS: In an existing West-African cohort, 783 healthy infants with a birth weight of at least 2,000 g were followed up during their first year of life. The aim of the study was to investigate if Plasmodium falciparum infection of the placenta, assessed by placental histology, has an impact on several anthropometric parameters, measured at birth and after three, six and 12 months using generalized estimating equations models adjusting for moderate low birth weight. RESULTS: Independent of LBW, first to third born infants who were exposed to either past, chronic or acute placental malaria during pregnancy had significantly lower weight-for-age (-0.43, 95% CI: -0.80;-0.07), weight-for-length (-0.47, 95% CI: -0.84; -0.10) and BMI-for-age z-scores (-0.57, 95% CI: -0.84; -0.10) compared to infants born to mothers who were not diagnosed with placental malaria (p = 0.019, 0.013, and 0.012, respectively). Interestingly, the longitudinal data on histology-based diagnosis of PM also document a sharp decline of PM prevalence in the Sukuta cohort from 16.5% in 2002 to 5.4% in 2004. CONCLUSIONS: It was demonstrated that PM has a negative impact on the infant's subsequent weight development that is independent of LBW, suggesting that the longer term effects of PM have been underestimated, even in areas where malaria transmission is declining.