By Lesley Odendal

Children born to HIV-positive mothers were 25 to 40% less likely to be vaccinated for childhood diseases, according to findings from a study based on data from rural KwaZulu-Natal, presented at the Fourth South African AIDS Conference in Durban in early April.

The distance to mobile clinics was also a significant determinant of vaccination. Wealth index was a significant determinant for vaccinations given once, but for those vaccinations that required three visits to healthcare facilities, coverage was mediated by other factors, such as distance to the nearest road, since mothers have to overcome transport challenges more than once to complete the course of vaccinations.

Globally, vaccinations have led to reduced morbidity and mortality in children, with an estimated 2.9 million potential deaths prevented by vaccinations between 2000 and 2007, according to the World Health Organization.

However a cross-sectional study conducted among pregnant women in Rakai, Uganda, showed that children born to HIV-infected mothers were significantly less likely to be vaccinated (OR=2.21, 95% CI; 1.14 to 4.29).

To investigate the relationship between immunisation status of children and maternal HIV status, 2431 children in the Hlabisa district were included in a regression analysis by James Ndirangu from the Africa Centre for Health and Population Studies, at the University of KwaZulu-Natal.

The sample included all children born between January 2004 and December 2005 and resident in the area covered by the Africa Centre’s demographic survey, an ongoing research project in a rural district in northern KwaZulu-Natal.

Maternal HIV status was found to be positive for 890 (36.6%) and negative for 275 (11.5%) of the mothers. More than half of the mothers (52.1%) did not know their HIV-status.

Data were collected from each child’s Road to Health (RTH) card and mothers were also requested to recall the vaccinations of their children.

After adjusting for maternal age, maternal education, household wealth and distance to the nearest road, mobile clinic or fixed clinic, it was found that children born to HIV-positive mothers were 40% less likely to have received a BCG vaccination than those born to HIV-negative mothers.

For the polio, DTP and hepatitis B vaccinations, which must be administered three times, it was found that children born to HIV-positive mothers were 36% less likely to have received the vaccinations than those born to HIV-negative mothers (p = 0.05).

Possible reasons for HIV-positive mothers to be less likely to vaccinate their children may be due to maternal HIV-related diseases and weakness. Another factor that may be contributing to the lower rate of immunisation is the time and resources mothers have to devote to accessing antiretroviral treatment, especially in this rural setting. Fear of stigmatisation is also a suggested factor, with mothers not wanting to attend facilities where their status may be known.

Distance to mobile clinic was also a significant determinant of vaccination. Sixty-five per cent of mothers in the study area walk for one hour or more to the nearest clinic.

The median distance to the nearest road was 2.01 km, while the median distance to the nearest mobile clinic was as much as 5.77km and to the nearest fixed clinic was 3.11km. The relative distance to mobile clinics as opposed to fixed clinics is also a contributing factor, as fixed clinics provide comprehensive primary care while mobile clinics are specifically for vaccination, family planning and antenatal care.

Future interventions to improve vaccination coverage should take into account the relationship between maternal HIV status and vaccination coverage. Specific vaccination campaigns which target HIV-positive mothers should be carried out at community and individual level to improve coverage. This is especially important given that the children of many of the HIV-positive mothers may be HIV-positive themselves and hence more likely to fall ill with the diseases they need to be vaccinated against.

Reference
Ndrirangu J. Is maternal HIV status associated with child vaccination status? Data from rural KwaZulu-Natal. Fourth South African AIDS Conference, Durban, abstract 102, April 2009.

By Lesley Odendal

Participation in a basic home stimulation programme can lead to improvements in both motor and cognitive development in HIV-positive children under 30 months, according to findings from a study presented at the Fourth South African AIDS Conference in Durban in early April.

The results of this study also support the inclusion of developmental screening and long-term management of all children who are infected with HIV, especially those in developing countries who do not have easy access to antiretroviral therapy.

Dr Joanne Potterton of the University of the Witwatersrand and colleagues conducted a randomised controlled trial to measure the impact of the home stimulation programme on the neurodevelopment status of HIV-positive children.

HIV is neurotropic (i.e. a virus capable of affecting nerve cells) and hence can have a negative effect on the development of the central nervous system. Many questions remain regarding the natural progression and pathogenic mechanisms of HIV-related central nervous system disease in children.

Affected children initially present with developmental delay, failure to achieve development milestones and deterioration of intellectual abilities. Although HIV affects all facets of neural development, children may present with spastic quadriparesis (a spastic rigidity of the limbs often accompanied by difficulty in swallowing and seizures), dystonic posturing (abnormal or `locked in` movements) and regression in motor milestones as the disease progresses. 

Understanding the impact of HIV on development is critical given that the rehabilitation needs of HIV-positive children on antiretroviral therapy (ART) will increase as the chronic manifestations of HIV infection become more apparent.

For this study, 122 HIV-positive children were recruited from a paediatric HIV clinic at Chris Hani Baragwanath hospital in Soweto, South Africa.

After randomisation, children in the control group continued to receive all the standard services at the clinic while children in the experimental group received a home stimulation programme in addition to the standard services.

The aim of the home programme was to optimise the child’s functional potential and to encourage age-appropriate activities and normal movement patterns. All children were seen at their routine clinic visits every three months. Baseline demographic information was collected and children’s heights, weights and head circumferences were measured at each visit. The home programme was updated at each visit.

Developmental status of the children was assessed using the Bayley Scales of Infant Development II, by a blinded assessor at baseline, six and twelve months. This included measuring change in cognitive (MDI) and motor (PDI) developmental status over time.

For MDI, the amount of change that occurred over time was significantly greater in the experimental group compared to the control group (p=0.01).  Although improvements occurred in both groups over time, the amount of improvement in the experimental group was significantly greater than that in the control group (p=0.02).

Children who were older, in the experimental group and from a household with a higher income were more likely to show an improvement in MDI over a one-year period. Improvements in PDI over one year were more likely in children who were older, in the experimental group and on ART.

The results of the study suggest that ART may have a positive impact on motor development.

The baseline developmental scores were extremely low for both MDI and PDI. Poverty, malnutrition and lack of access to antiretroviral therapy may all contribute to these very low scores. Although the children in the experimental group did improve through the use of the basic home programme, they remained delayed and need further long-term follow-up, according to the study.

While the findings from this study have positive implications for the neurodevelopment of HIV-positive children, the study also illustrates that South African children who are infected with HIV are at risk of severe cognitive and motor delay. While the participation in a basic home stimulation programme led to improvements in both motor and cognitive development, the results of this study also support the inclusion of developmental screening and long-term management of all children who are infected with HIV, especially those in developing countries who do not have easy access to antiretroviral therapy.

Reference
Potterton, J The Effect of a home stimulation programme on the neurodevelopmental status of children infected with HIV in Soweto, South Africa. Fourth South African AIDS Conference, Durban, South Africa, abstract 450, April 2009