Language development worse among HIV-exposed two-year-olds
Delayed language development found in HIV-negative two-year-olds exposed to the virus during pregnancy.
HIV-negative children exposed to HIV and antiretroviral treatment (ART) during pregnancy, birth and breastfeeding have a greater odds of delayed language development, suggests a new study.
The global success of prevention of mother-to-child transmission (PMTCT) programmes means that the majority of children born to mothers living with HIV are now born HIV-free. UNAIDS estimates that 14·8 million infants exposed to HIV during pregnancy in 2018 did not acquire the virus.
The research, the largest long-term study of its kind, is the first to show clear delays in receptive and expressive language at 24 months among children exposed to HIV who remain HIV-negative.
Earlier studies suggest infants and children who become HIV-positive from transmission during pregnancy have increased odds of developmental delay. But whether HIV-exposed infants who remain HIV-negative are affected in similar ways is currently unclear, with some research suggesting delays occur and others finding no evidence of this.
To add to this body of evidence, researchers compared the neurodevelopment of infants and children who had been exposed to HIV but remained HIV-negative with infants and children who had not been exposed to the virus during their first two years of life.
Few studies have investigated children exposed to current first-line antiretroviral drug treatment (ART) in sub-Saharan Africa, and most have not documented infants during breastfeeding, which is itself associated with neurodevelopment.
Between 2012 and 2015, more than 1,000 pregnant women were enrolled in the study while attending antenatal appointments at two suburban clinics in Paarl, Western Cape, South Africa, where around 21% of pregnant women are estimated to be living with HIV.
Less than 20% of mothers enrolled exclusively breastfed for six months after giving birth and all infants and children exposed to HIV during the study received antiretrovirals.
Six months after birth, development assessments, measured using the Bayley Scales of Infant and Toddler Development, were conducted on 260 randomly selected infants, 61 of whom had been exposed to HIV but were HIV-negative and 199 who had not been exposed to HIV.
At 24 months, assessments were also carried out on 732 randomly selected children, 168 of whom had been exposed to HIV but were HIV negative and 564 who had not been exposed to HIV. On both occasions, the researchers carrying out the assessments did not know whether the infants and children they were assessing had been exposed to HIV or not.
Researchers found development did not significantly differ between groups at six months. However, at 24 months, HIV-exposed, HIV-negative children scored lower than HIV-unexposed children for receptive and expressive language, suggesting clinically significant impairment. No significant differences were found between groups in relation to cognitive, fine motor or gross motor skills.
The association between exposure to HIV and poorer language outcomes remained, even after infant feeding methods, maternal depression and prematurity were taken into consideration.
However, the level of HIV within the mother was found to be a mitigating factor, with maternal CD4 cell counts of 500 cells/mL or fewer associated with poorer language outcomes, suggesting that maternal viral load might predict poorer developmental outcomes for infants.
What wasn’t examined was whether parent-to-child interaction, which is in turn affected by a caregiver’s physical or psychological health, might have affected language development. The possible impact of antiretroviral neurotoxicity was also not examined. This was due, in large part, to the challenging nature of separating the effects of antiretroviral treatment from the effects of the virus itself.
The study’s findings are consistent with research conducted in the USA, the Democratic Republic of the Congo, Botswana and Uganda on HIV-exposed, HIV-negative infants and children, all of which found evidence of language impairment.
Further long-term research is needed to understand the developmental outcomes of children exposed to HIV who remain negative, particularly whether certain subgroups of this population might be more susceptible to language delays than others. This is especially pressing in regions such as east and southern Africa, where many infants are exposed to HIV.
Commenting on the research in The Lancet, Alta Kritzinger, Associate Professor at the Department of Speech-Language Pathology and Audiology at the University of Pretoria, said: “Since the increased susceptibility of the HIV-exposed uninfected infant population to language delay has become clearer, informing caregivers of the risk, without alarming them, is a professional responsibility. Increased child-care support to mothers with HIV is important... Another area in need of support is breastfeeding, as highlighted by the low prevalence in this study's sample.”
This “birth cohort study makes an important contribution to the current understanding of the neurodevelopment – and particularly the language development – of the expanding population of children with prenatal exposure to HIV and antiretroviral therapy.”