Post-natal maternal antiretroviral therapy and HIV prevalence among breast-fed infants in Benin, Nigeria.

BACKGROUND: Breastfeeding is an established mode of transmission of human immunodeficiency virus (HIV) infection resulting in clash between socio-cultural values and medical practice. AIMS: This study aims to determine the effect of post-natal maternal antiretroviral therapy on transmission of HIV through breastfeeding. PATIENTS AND METHODS: A total of 318 pregnant women were followed from pregnancy to 6 months post- partum. The women were divided into breast-fed and those who did not breast-feed, while the breast-fed were further divided into those on antiretroviral (ARV) and those not on ARV. After 6 months post-partum, dried blood spots were collected from infants born to these women and tested for HIV using polymerase chain reaction.
RESULTS: Generally, breast-feeding had 4 to 13 fold increase risk of transmission of HIV to infants (OR =7.079 95% CI = 3.768, 13.300; P <0.0001). However, among breast-fed infants, post-natal maternal ARV resulted in reduced prevalence of HIV compared to mothers who did not use ARV during breast-feeding (17.31% VS 92.00%; P<0.0001).
CONCLUSION: The study demonstrates the effectiveness of post-natal maternal ARV. However, research into better feeding options to prevent mother to child transmission of HIV via breast-feeding is advocated.

Introduction

Breastfeeding is an integral part of a woman's motherhood and it is estimated that HIV transmission through breast-milk results in 200,000 HIV new cases yearly[12]. It has already been reported that HIV can be transmitted through breast-feeding[1-3]. In resource-poor setting, it is difficult for mothers not to breast-feed their babies and one study has shown that mortality and morbidity rates were similar for both formula-fed and breast-fed infants[4]. Because of the stigma associated with HIV infection, most women choose to breast-feed to avoid the risk of revealing their HIV status. Many care givers are faced with these problems as conflicting reports exist on the benefits of exclusive breast-feeding, mixed feeding and formula feeding[5-7].

The availability of highly active antiretroviral therapy (HAART) during pregnancy in combination with avoidance of breast-feeding and elective caesarian section has been reported to reduce or nearly eliminate mother to child transmission of HIV in developed countries[8]. A number of practices have been recommended by various researchers to reduce post-natal HIV transmission[18].

In our setting, exclusive formula feeding is recommended as a policy for HIV positive women. The stigma associated with HIV infection makes HIV infected women still breast-feed as avoiding breast-feeding may indicate a positive HIV status to her relatives or in-laws, thus bringing a clash between societal acceptance and medical practice. Against this background, this study is aimed at determining the effect of post-natal maternal antiretroviral therapy and breast-feeding on the prevalence of infant HIV infection.

Patients and Methods

Study Area

This study was carried out in University of Benin Teaching Hospital, Benin City, Nigeria. The hospital is a tertiary hospital with a referral status and is one of the sites for Institute of Human Virology, Nigeria (IHVN) and the President Emergency plan for AIDS Relief (PEPFAR) HIV/AIDS intervention program in the country. HIV testing, treatment and monitoring are rendered at no cost and some of the patients were used in this study.

Study Population

A total of 318 HIV-positive pregnant women on their third trimester and on antiretroviral (ARV) drugs were recruited for this study. Each pregnant woman was counseled and informed about the study protocol. Verbal informed consent was obtained from each woman and her spouse prior to commencement of study.

Based on consent from the women and their spouses, the women were divided into two groups. Those that will exclusively breast-feed their babies and those that will not. This was further divided into those that will continue ARV and those that will not. The exclusive breast-feeding was for a period of 6 months after which infants born to these women were all screened for HIV using polymerase chain reaction (PCR). The protocol for this study was approved by the Ethical Committee of the University of Benin Teaching Hospital.

Collection and processing of samples

A drop of blood from finger prick of each infant was placed on sterile Whatman No 903 filter paper and allowed to dry as dried blood spot. The dried blood spots (DBS) collected from each infant were tested for HIV using a qualitative DNA polymerase chain reaction (PCR) (AMPLICOR® HIV-1 DNA test version 1.5, Roche).

Statistical analysis

Data were analyzed using odd ratio analysis using the statistical software INSTAT®. A P value <0.05 was considered significant.

Results

The prevalence of post-natal HIV infection was significantly higher (P<0.0001) in breast-fed infants compared with their non-breast-fed counterpart and breastfeeding was a risk factor for acquiring HIV infection among infants (OR=7.079 95%CI=3.268, 13.300; Table 1).

Table 1

Effect of Breast-feeding on prevalence of HIV among infants

The use of ARV during breastfeeding was not associated with post-natal HIV infection among infants (OR=0.018 95%CI=0.004, 0.091). None use of ARV during breastfeeding period was significantly (P<0.0001) associated with post-natal HIV infection (OR=54.944 95%CI=10.938, 276.00; Table 2).

Table 2

Effect of antiretroviral usage and breast feeding on the prevalence of HIV among infants

Discussion

Against the background of conflicts between societal pressure to breast-feed (with the risk of exposing one's status and thus stigmatization) and medical practice to reduce the prevalence of post-natal HIV among infants, this study focused on determining the effect of prolonged maternal antiretroviral therapy and breast-feeding on the prevalence of infant HIV infection in Benin City, Nigeria.

A total of 54 (16.98%) out of 318 infants born to HIV positive mothers were infected with the HIV virus. Women who breast-fed exclusively had approximately 4 to 13 fold increase ask of acquiring HIV infection compared to their non-breastfed counterpart. This finding is similar to earlier reports[910] and substantiates the policy in our setting. However, a number of studies have indicated increased risk of infant morbidity and mortality associated with replacement feeding[311]. Inability to afford infant formula and poor condition for preparation of replacement feeding has been suggested as possible reasons for the high morbidity and mortality among formula-fed infants[3]. Although the current practice in our setting may be beneficial in reducing mother to child transmission of HIV infection, it is important to note that infectious diseases and malnutrition are the primary causes of death during infancy and artificial feeding substantially increases children risk of illness and death[2].

Considering breast-fed infants, women who were on ARV throughout the breast-feeding period had significantly lower prevalence of HIV infection among their infants compared to infants born to women who were not on ARV during the breast-feeding period. This shows a beneficial effect of ARV during breast-feeding period and indeed it has been reported that exclusively breast-fed infants acquire infection after 6 months, once all exclusive breast-feeding has ceased[9]. Although one may not generally say that exclusive breast-feeding of infants born to HIV infected mothers should be a general policy as the sample size for this study was small and an HIV prevalence of 17.3% was observed, the benefit of post maternal ARV is clear. Perhaps future studies that will combine breast-feeding, maternal ARV and neonatal antiretroviral therapy may be able to bridge societal pressure to breast-feed against medical practice to reduce mother to child transmission of HIV through breast-feeding. Kumwenda et al.[12] had suggested antiretroviral prophylaxis for infants throughout the breast-feeding period to reduce HIV transmission and increase HIV free survival.

Conclusion

This study has shown a reduced infant HIV infection among exclusively breast-fed infants whose mothers were on ARV during the breast-feeding period, although generally, non breast-fed infants had lower prevalence of infants HIV infection. Research into new feeding and antiretroviral therapy patterns to resolve the conflict between societal demand and medical practice is advocated.