Mother-to-child transmission of HIV and its predictors among HIV-exposed infants at a PMTCT clinic in northwest Ethiopia

The HIV pandemic created an enormous challenge to the survival of humankind worldwide. At the end of 2011, an estimated 34 million people were living with HIV globally. There was 2.5 million new HIV infections, including 330, 000 among children less than 15 years. The annual number of people dying from AIDS-related causes worldwide is steadily decreasing. In 2011, 1.7 million people worldwide died from AIDS related causes, down 24% from the peak in 2005 [1].

Besides the dominant heterosexual transmission, vertical HIV transmission from mother to child accounts for more than 90% of paediatric AIDS. PMTCT programs provide for both prevention of HIV transmission from mother to child and enrolment of infected pregnant women and their families into antiretroviral treatment (ART). It is undertaken by the government of Ethiopia in an effort to mitigate the impacts of the epidemic in the general population and amongst children in particular. The availability and use of short-course antiretroviral (ARV) prophylaxis-a safe and well-tolerated regimen-can contribute significantly to PMTCT during childbirth [2].

Ethiopia is one of the countries most severely hit by the epidemic. According to Ethiopian demographic and health survey 2011, the national adult HIV prevalence is reported to be 1.5% (4.2% in urban and 0.6% in rural areas) [3]. Highest prevalence occurs in the 15–24 age groups and prevalence is higher among females than males in both urban and rural areas. Prevalence appears to have levelled off in urban areas but continues to rise in rural areas, where 85% of the population lives [2].

Ethiopia has adopted the World Health Organization (WHO) four pronged PMTCT strategy as a key entry point to HIV care for women, men and families. These are: primary prevention of HIV infection, prevention of unintended pregnancies among HIV-infected women, prevention of HIV transmission from HIV-infected women to their offspring, provision of care and support to women infected with HIV, their infants and families [4].

Although there are reports on the effectiveness and outcomes of PMTCT from many countries, there are limited studies conducted in Ethiopia to assess the risk of HIV transmission and its predictors among exposed infants. One retrospective study conducted in Addis Ababa, Ethiopia, showed 11.8% HIV prevalence among exposed infants [5]. Provision of baseline information about the risk and predictors of HIV transmission among HIV exposed infants is of immense importance. This study thus aimed to assess the risk of HIV transmission and its predictors among HIV exposed infants who had follow up at PMTCT clinic of Gondar University Hospital.

Institution based retrospective follow up study was carried out among infants and mothers who were on follow up at the PMTCT clinic.

A total of 521 mother-infant pairs were enrolled in to the PMTCT clinic during the study period. Among these, 509 records were included in the final analysis. Twelve records were incomplete and excluded. The median age at enrolment to HIV-exposed infant follow up clinic was 6 weeks (IQR = 2 weeks). Nearly half (51.7%) of them were males and majority (83.3%) were from urban areas. Three hundred sixty eight (81.2%) of the mothers were enrolled to ART clinic. However, 92(18.1%) mothers did not receive any PMTCT interventions during pregnancy and child birth. Majority (90.4%) of the exposed infants were born at a health institution. Almost all (97.8%) mothers were alive when infants started follow up and majority (85.1%) of the infants took ARV prophylaxis at birth (Table 1).

At enrollment, most (78.8%) infants were on exclusive breast feeding, 67(13.3%) on exclusive replacement feeding, while the rest 40(7.9%) were on mixed feeding. Forty three (8.4%) infants had diagnosis suggestive of HIV infection. The most common diagnosis was Pneumonia/Lower respiratory tract infections, followed by persistent diarrhea and hepato-spleenomegaly. More than three quarters (80.5%) of the infants started cotrimoxazole prophylaxis at enrolment.

Prevention of mother-to-child transmission of HIV-1 is a major public health challenge in many resource-poor countries including Ethiopia. This study was based on a retrospective analysis of data from a routine PMTCT program in a referral hospital. According to this study, among HIV-exposed infants on follow up at the PMTCT clinic of Gondar University referral hospital, one-tenth of HIV-exposed infants got HIV-infected. We included only those infants whose mothers were tested HIV-positive and followed up until the infant’s HIV status was confirmed.

Compared to high income countries (<2%) [6, 7], and reports from India (6.5%) and South Africa (5.9%) [8, 9], in our study risk of MTCT was very high. This may be due to the universal use of highly active antiretroviral therapy for pregnant women, elective caesarean sections and avoidance of breastfeeding in developed countries [10]. However, such preventive approaches are limited in poor countries due to poor funding, social and cultural norms [11].

Factor that put an infant to a higher risk of HIV transmission were; late enrolment to the follow up clinic, rural residence, home delivery, absence of maternal PMTCT interventions and mixed infant feeding practices. The reasons for the high relevance of these factors could be overlapping to one another. Firstly, infants born from rural mothers are prone for mixed feeding. Secondly, rural mothers are less likely to screen and enroll themselves to antenatal care or health institution delivery and thereby less likely to benefit from PMTCT interventions. As a result many women in resource-poor countries do not have access to prenatal care and often present with infection lately [12]. All these health care disadvantages in the rural settings compared to the urban areas would put infants of rural mothers at a higher risk of MTCT of HIV and thereby mortality [10].

Similar to studies done so far in different corners of the world [9, 13, 14], if the mother received PMTCT interventions during pregnancy, the risk of MTCT of HIV was only 4.8%. The result of this study is in line with the widely accepted fact that providing ARVs to both the mother and the newborn prevents MTCT of HIV [15]. In this study, the risk of MTCT was 40.5% among infants with no prophylaxis, 5.1% for infants who received sdNVP prophylaxis and 4.9% for infants who took combined (sdNVP + AZT) prophylaxis. The difference was significant between no prohylaxis and sdNVP groups. However, there was no statistical difference between sdNVP and combined (sdNVP + AZT) prophylaxis regimens. This is similar to previous studies reporting a higher benefit of ARV prophylaxis to exposed infants [5, 9, 13] especially with combined regimens. A cohort study in Abidjan, Côte d’Ivoire, reported a 72% reduction of MTCT [16] with ZDV + sdNVP compared to ZDV alone while another study reported an increasing drug number and duration would significantly decrease the risk of MTCT [9]. However, this difference was not observed in the current study partly due to the lower sample size.

There is a high risk of MTCT of HIV among exposed infants on follow up at the PMTCT clinic of the University of Gondar referral hospital. The risk of MTCT of HIV was higher among those from rural areas, enrolled after six weeks of age, had no maternal PMTCT intervention, delivered at home and mixed fed infants. The findings of this study will provide valuable information for policy makers in the PMTCT scaling-up program to focus on rural settings.

Both authors contributed equally in the design, data collection and write up of this manuscript. Both authors read and approved the final manuscript.