"Maternal HIV Status & Risk of Infant mTB Infection as Measured by Tuberculin Skin Test"
Find full article: Maternal HIV Status and Risk of Infant Mycobacterium tuberculosis Infection as Measured by Tuberculin Skin Test - PubMed (nih.gov)
Background:
The effect of maternal HIV on infant Mycobacterium tuberculosis (Mtb) infection risk is not well-characterized.
Methods:
Pregnant women with/without HIV and their infants were enrolled in a longitudinal cohort in Kenya. Mothers had interferon gamma-release assays (QFT-Plus) and tuberculin skin tests (TST) at enrollment in pregnancy; children underwent TST at 12 and 24 months of age. We estimated the incidence and correlates of infant TST-positivity using Cox proportional hazards regression.
Results:
Among 322 infants, 170 (53%) were HIV-exposed and 152 (47%) were HIV-unexposed. Median enrollment age was 6.6 weeks [interquartile range (IQR): 6.1–10.0]; most received Bacillus Calmette-Guerin (320, 99%). Thirty-nine (12%) mothers were TST-positive; 102 (32%) were QFT-Plus-positive. Among HIV-exposed infants, 154 (95%) received antiretrovirals for HIV prevention and 141 (83%) of their mothers ever received isoniazid preventive therapy (IPT). Cumulative 24-month infant Mtb infection incidence was 3.6/100 person-years (PY) [95% confidence interval (CI): 2.4–5.5/100 PY]; 5.4/100 PY in HIV-exposed infants (10%, 17/170) versus 1.7/100 PY in HIV-unexposed infants (3.3%, 5/152) [hazard ratio (HR): 3.1 (95% CI: 1.2–8.5)]. More TST conversions occurred in the first versus second year of life [5.8 vs. 2.0/100 PY; HR: 2.9 (95% CI: 1.0–10.1)]. Infant TST-positivity was associated with maternal TST-positivity [HR: 2.9 (95% CI: 1.1–7.4)], but not QFT-Plus-positivity. Among HIV-exposed children, Mtb infection incidence was similar regardless of maternal IPT.
Conclusions:
Mtb infection incidence (by TST) by 24 months of age was ~3-fold higher among HIV-exposed children, despite high maternal IPT uptake. Overall, more TST conversions occurred in the first 12 months compared to 12–24 months of age, similar in both HIV-exposed and HIV-unexposed children.
Millions of children are exposed to Mycobacterium tuberculosis (Mtb) every year.1 Early Mtb infection identification in young children is important, due to the substantially increased risk of developing tuberculosis (TB) within 1–2 years following infection without intervention, which is approximately 20% among children under 5 years of age.2 Children born to mothers with HIV may be predisposed to early Mtb infection due to increased TB exposure.3–5 HIV-exposed children may be more immunologically vulnerable as a result of HIV exposure in utero and potentially reduced cellular response to Bacillus Calmette-Guerin (BCG) vaccination.3,6–8
Previous estimates of Mtb infection among HIV-exposed infants have been primarily prior to universal maternal antiretroviral therapy (ART).3,4,9,10 Whether maternal HIV increases susceptibility to infant Mtb infection under contemporary conditions of widespread maternal ART and programmatic isoniazid preventive therapy (IPT) is unknown.
We conducted a prospective longitudinal cohort study of children with and without HIV exposure, enrolled at 6 weeks of age and serially tested for Mtb infection at 12 and 24 months of age measured by tuberculin skin test (TST). For this analysis, we estimated cumulative infant Mtb infection incidence overall and by HIV exposure, compared incidence of Mtb infection between the first and second year of life, and assessed correlates of infant Mtb infection.
