March 24, 2020
World TB Day 2020: Researchers explore preventative interventions to stop TB infections in children and pregnant women
The observation of World TB Day each year on March 24th provides an opportunity to raise awareness about tuberculosis (TB) and the measures needed to find, treat, and prevent this devastating disease that surpasses HIV as the leading infectious cause of morbidity and mortality worldwide. With the success of HIV treatment globally, most children born to mothers living with HIV will remain HIV-negative. However, these HIV-exposed children remain at high risk for Mycobacterium tuberculosis (TB) infection and disease.
Over one million new cases of TB and 239,000 TB-related deaths occur in children each year. Despite evidence that HIV exposure in children is associated with an increased risk of TB infection and development of TB disease, few studies have explored the ways in which children born to mothers living with HIV become susceptible to TB infection. Exposure to their mother’s HIV and HIV treatment (anti-retroviral therapy (ART)) prior to birth may influence subsequent immune responses to TB infection, especially in early childhood. Global WACh’s NIH-funded “The effect of HIV exposure and infection on immunity to TB in children” (PI: John-Stewart [UW], Day [Emory University]) study utilizes specimens from three cohorts of infants and children in Kenya. Since the study launched in December 2019, the team has been studying the differences in immune responses between HIV-infected, HIV-exposed uninfected, and HIV-unexposed children to gain insight into the association between HIV and TB infection in infants and children. Such insight will inform novel TB preventive interventions, such as vaccines, in HIV-infected and HIV-exposed children.
For infants, risk of progression from TB infection to TB disease is 30-50% without intervention, especially in the first year of life. Infants are also more likely to develop the most severe forms of TB disease that can be fatal. At the Conference on Retroviruses and Opportunistic Infections (CROI) on March 11th, Dr. Sylvia LaCourse (Assistant Professor, Medicine – Allergy and Infectious Diseases and Global Health), a co-investigator of Global WACh’s infant TB Infection Prevention (iTIPS) study, described the findings of whether isoniazid, a medicine used routinely to prevent TB disease TB, could be used to prevent TB infection in infants born to mothers living with HIV. Though more research is required, the results displayed a trend of lower infection rates among infants who received isoniazid for 12 months compared to infants who did not. Isoniazid was safe to use and did not cause adverse health effects. View the abstract here and watch the presentation here.
As researchers focus on safety and efficacy of preventative treatments to develop evidence-base guidelines, Dr. LaCourse and collaborators highlight knowledge gaps in TB prevention for pregnant and postpartum women living with HIV and advocate for their inclusion in clinical trials. Read their viewpoint article in the Journal of the International AIDS Society titled, TB prevention strategies and unanswered questions for pregnant and postpartum women living with HIV: the need for improved evidence.
To learn more about Global WACh studies and publications focused on TB and HIV co-infections, visit our website and read our World TB Day 2019 post.