Group B Streptococcal carriage and HIV-infection in pregnant women in Malawian women
Dr George Kafulafula, Dr Katherine Gray, Dr Neil French
- Start Date:
01 January 2008
London School of Hygiene & Tropical Medicine, London, UK, Queen Elizabeth Central Hospital, Malawi-Liverpool-Wellcome Research Laboratories, College of Medicine, Blantyre, Malawi
Group B Streptococci (GBS) are the most important identified infectious cause of neonatal death in Blantyre, Malawi. The incidence of meningitis and septicaemia (1.8/1000 live births) is similar to that in industrialised countries before maternal chemoprophylaxis was introduced. The mortality rate of GBS disease in Blantyre is 35% in a population where the live birth rate is 37/1000 and neonatal mortality is 27/1000 live births.
GBS has emerged as an important neonatal problem in southern and eastern Africa only recently raising the issue of a link with Human Immunodeficiency Virus (HIV) infection. Defects in immune response to capsulate bacteria are a feature of HIV-infection (e.g. pneumococcal infection).
GBS carriage leads to invasive infection in neonates in between 1-2% of children exposed at birth. With increasing numbers of HIV-infected women (as a consequence of improved survival with antiretrovirals) understanding whether HIV-infected pregnant women are more likely to carry GBS is important for defining appropriate control measures such as peri-partum chemoprophylaxis or vaccination.
To investigate the association between GBS carriage and HIV status we propose to recruit approximately 2000 pregnant women (20% HIV-infected) in late third trimester attending the antenatal services at the Queen Elizabeth Central Hospital in Blantyre. Participants will have rectal and vaginal swabs collected, be HIV tested and provide basic demographic medical and reproductive data along with CD4 counts if relevant. GBS isolates will be serotyped. The study will have 80% power at 5% significance (two-tailed) to show an increased carriage of 40% or greater.