Thanks to effective antiretroviral programmes, far fewer children have been infected with HIV through vertical transmission (mother-to-child transmission) in recent years. Consequently, the number of children who are HIV-exposed but uninfected is increasing. In 2022, there were an estimated 16 million CHEU (Children who are HIV-Exposed but Uninfected) worldwide, with around one million more born each year. In recent years, research has increasingly focused on CHEU facing a higher risk of morbidity and mortality, particularly from infectious diseases such as tuberculosis (TB).
Researchers including joint first author Dr Laura Olbrich, DPhil, from the Institute of Infectious Diseases and Tropical Medicine at LMU University Hospital Munich, examined this link in more detail. In a narrative review published in The Lancet Global Health, they discuss existing research on CHEU in order to better understand how tuberculosis affects these children and to identify gaps for future research and prevention.
To do so, the authors used an iterative search strategy in which they conducted a step-by-step literature search and continuously refined their search by repeatedly reviewing and adjusting search terms and results to identify key studies and findings on tuberculosis in children: Each year, an estimated 7.5 million children are infected with Mycobacterium tuberculosis, and more than one million develop tuberculosis disease. Young children are particularly vulnerable. The risk of severe disease and death is highest in children under five and in those with weakened immune systems, such as children living with HIV.
Evidence also indicates that HIV exposure alone may affect the risk for tuberculosis infection and disease, likely due to immune alterations, reduced responses to BCG vaccination against TB, and social or nutritional challenges. However, the underlying biological mechanisms and social factors remain unclear. The authors stress the need for more cohort studies comparing CHEU, HIV-unexposed children, and children living with HIV in high-burden settings. „As the global population of CHEU continues to grow, understanding their risk of tuberculosis will be essential for developing targeted prevention and care strategies“, says Dr Laura Olbrich, DPhil.
