The HIV-Exposed but Uninfected (HEU) Infant: How Can the Excess Morbidity and Mortality be Explained?

This project has expanded beyond the initial STIAS realm and is the outgrowth of an initiative developed between STIAS and the Peter Wall Institute for Advanced Studies (PWIAS), associated with the University of British Columbia. An interdisciplinary colloquium, the first Peter Wall Colloquium Abroad, was held at STIAS in November 2009 and sought explanations for why babies exposed to HIV but uninfected by their mothers are at enhanced risk of poor health and development during the first year of life.

This interdisciplinary colloquium was organised and sponsored within the framework of a formal partnership agreement between STIAS and PWIAS and took place against the following background.

Every year, approximately 10.6 million children die before the age of five years, mostly in low or middle income countries. Approximately 20% of babies in South Africa are born to mothers who are infected with HIV, and with effective mother to child prevention of transmission programs the rate of transmission to the babies during pregnancy and delivery can be as low as 5%. For reasons that remain to be explained, babies exposed to HIV but uninfected (HEU) by their mothers are at enhanced risk of poor health and development during the first year of life.

The two-day meeting was attended by researchers and clinicians from South Africa, Zimbabwe, Canada, Belgium and the United States. A total of 20 attendees presented papers and discussed the multiple dimensions of this problem in an attempt to plan a study to explain this peculiar phenomenon. Potential contributing factors include poverty, malnutrition, lack of access to health care and exposure to adverse environmental factors and/or transmissible infectious diseases. Nonetheless, many children exposed to HIV remain healthy. It remains unclear why some children fall ill and others thrive despite exposure to apparently similar environmental and social challenges. It is essential to better understand the spectrum and determinants of HIV-related health and disease in children from low and middle income countries as the first step in their prevention.

Susceptibility to disease of any type is multifaceted, involving, among other factors, genetics, environmental exposures (toxins, pollution, microbes), nutrition and psychosocial conditions. Many studies have been performed in the developed world to identify the factors that put children at risk for suffering from HIV-related illnesses, but none has identified severe disease in those babies who are not infected (HEU). There is a dearth of information from the developing world where this phenomenon has now been identified in sub-Saharan Africa and in South America. Analyses can be performed at a point in time (by case control) or in a prospective study. Whereas the latter is more expensive than the former, a cohort study has many advantages and is most likely to inform strategies for enhancing the care of children in resource-limited settings. A longitudinal study at Tygerberg Hospital in Cape Town, South Africa is currently being conducted to identify why HEU babies suffer so much illness during the first year of life

A number of follow-up collaborative projects between SU, UBC and other institutions have also resulted.

[SU Researchers: Mark Cotton, Monika Esser, Mariana Kruger and Ben Marais]

Project leader(s):
  • David Speert (U British Columbia)