Institute: Centre for International Child Health, Imperial College London
Biography
My main research interests are the effect of maternal immunity of infant disease.
Group-B Streptococcal (GBS) disease is a major cause of infant mortality and morbidity globally. In low/middle income settings, the disease burden remains uncertain although in several countries of Southern Africa appears comparable to that of high-income countries (1.4/1000 live births). Colonization rates in pregnant women range from 12-50% and around 50% of their infants will be colonized. Of these, ca. 1% are known to develop GBS disease with 10% mortality and subsequent severe disability in up to 50% in survivors of GBS meningitis. Early-onset disease (EOD) is caused by transmission from a colonized mother to her newborn infant. Late-onset disease (LOD) occurs both from colonization and environmental factors. Protection from neonatal invasive disease is known to be associated with maternal antibody to certain GBS-serotypes. Therefore, maternal immunization to elicit antibody to be transmitted via the placenta and protect newborns represents an attractive disease prevention strategy for both EOD and LOD. However, phase III trials of GBS vaccines, now in clinical development, are hampered by large sample numbers required to prove efficacy. It is widely acknowledged that availability of a surrogate marker would have enormous impact as an alternative endpoint in clinical trials aimed at licensure.
Since there are geographical differences in strain distribution, the global effectiveness of GBS vaccines currently in development is unknown, and GBS-serotype specific recent data from West Africa are lacking to predict potential impact. The effect of maternal GBS carriage on serotype-specific antibody transfer to her infant and subsequent antibody function, and the natural history of decline in antibody in infant blood and breastmilk has not been evaluated but matters for future vaccination strategies.
I am currently developing several studies to answer important questions about serocorrelates of protection, including the standardisation of GBS antibody assays.
Key Publications
A list of publications can be found here.
Web Links of Interest