Prevention of mother-to-child transmission of HIV-1 in Sub-Saharan Africa

 

Introduction

 

The World Health Organization estimates that approximately 40 million people are living with HIV/AIDS worldwide and that 28 million of these reside in sub-Saharan Africa. 55% of infected adults in sub-Saharan Africa are women. 90% of these women are in their reproductive years. Hetero-sexual transmission is the major route of HIV transmission in sub-Saharan Africa. HIV sero-prevalence in Sub-Saharan Africa is about 8.4% compared to 0.6% in North America. Out of the total 5 million new HIV infections in the world in 2001, 3.4 million occurred in sub-Saharan Africa.

 

Women and girls make up a growing proportion of those infected by HIV/AIDS. At the end of 2004, UNAIDS reported that women made up almost half of the 37.2 million adults (aged 15 to 49) living with HIV/AIDS worldwide. The hardest-hit regions are areas where heterosexual contact is the primary mode of transmission. This is most evident in sub-Saharan Africa, where close to 60% of adults living with HIV/AIDS are women.

The United Nations estimates that every day 6,000 young people aged 15 to 24 become infected with HIV. A staggering two-thirds of these new cases are adolescent women. Economic, social, and cultural factors contribute to the disparity of new HIV/AIDS cases between men and women.

Mother to child transmission of HIV

One of the tragic consequences of the HIV/AIDS pandemic is mother-to-child transmission (MTCT) of HIV. Mother to child transmission is when an HIV positive woman passes the virus to her baby. Mother to child transmission is the primary means by which young children become infected with HIV-1.  Mother to child transmission of HIV can occur during pregnancy, during labor and delivery, and after birth through breast feeding. Approximately 15-40% of children born to HIV positive mothers become infected.  Without treatment, around 15-30% of babies born to HIV-positive women will become infected with HIV during pregnancy and delivery. A further 10-20% will become infected through breastfeeding. Current evidence suggests that most of maternal-infant HIV transmission occurs late in pregnancy or during labor and delivery.  HIV-1 transmission from an infected mother to her baby is estimated to be 21-43% in the less developed countries, 1 with more than half of the transmission probably occurring late in pregnancy or during labour and delivery.

 

In 2004, around 640,000 children under 15 became infected with HIV2, mainly through mother to child transmission.  About 90% of these MTCT infections occurred in Africa, in particular sub-saharan Africa where AIDS is beginning to reverse decades of steady progress in child survival3. Worldwide, more than four million children are estimated to have died from AIDS, primarily contracted through MTCT.

 

Prevention of mother to child HIV transmission (PMTCT)

A four-fold strategy is needed to prevent MTCT: that is to prevent babies from acquiring HIV from their infected mothers.

Prevention of HIV among prospective parents: The best way to avoid MTCT is to prevent HIV infection among women of reproductive age. This can be done through economic empowerment of women, education of the girl child, premarital HIV counseling and testing (VCT), creating awareness through heath education programs.

Prevention of unwanted pregnancies among HIV-positive women is very important in the fight against MTCT of HIV. Through voluntary counseling and testing (VCT) services, women can be able to know their HIV status before becoming pregnant. Family planning services are needed to prevent unwanted pregnancies in HIV seropositive women. Unfortunately in sub-Saharan Africa majority of women do not have access to VCT and family planning (FP) services. Such services tend to be concentrated in the urban communities leaving out those women in the rural areas.

The care and treatment of HIV-positive pregnant women. In western countries MTCT has been virtually eliminated thanks to effective voluntary testing and counseling, access to antiretroviral therapy, safe delivery practices and the widespread availability and safe use of breast-milk substitutes. If these interventions were used worldwide, they could save the lives of approximately 300,000 children each year4. The risk of MTCT of HIV has dropped to as low as 2% among the limited number of HIV infected women in developed countries. In developing nations, however, particularly sub-Saharan African countries where the vast majority of HIV-infected women of child bearing age live, MTCT rates remain high. Such high rates persist mostly because of the lack of access to existing prevention interventions, including VCT, replacement feeding, elective caesarian section, and antiretroviral drugs.

Preventing the transmission of HIV from HIV-positive mothers to their infants during pregnancy, labour, delivery and breastfeeding5 can be achieved through improved antenatal care (ANC) services, providing  antiretroviral therapy to HIV positive women during pregnancy, safe delivery practices such as elective caesarian section, the use of breast milk substitutes to avoid MTCT of HIV through breast feeding. However in sub-Saharan Africa where almost half of the pregnant women do not even have access to basic ANC services or even safe drinking water; how then can we factor in these proven practices that have nearly eliminated MTCT in the developed nations? Based on UNICEF pilot programs, combined data from 9 African countries showed that , 43% of ANC attendees accepted VCT, 19% tested HIV+, and 39% of HIV+ pregnant women received ARV therapy. Combined data from call for action (CTA) program participants, among 110,000 total women tested at ANC, 90% were counseled, and 80% tested, and among 17% who tested positive 58% of women and 30% of their newborns received antiretroviral therapy6. In a kenyan program, 73% of women attending ANC were offered VCT, 89% offered VCT accepted, and of the 6% of women who tested HIV+, 64% accepted treatment (49/76)7. In Botswana, 56% of ANC attendees accepted counseling. 52% of those counseled were tested, 52% of women who tested HIV+ received ARV therapy and only 1/3 of those completed the course of therapy8. There certainly appears to be poor uptake of MTCT services among those few ‘lucky’ HIV+ women who have access to care. The challenge of PMTCT in sub-Saharan Africa is still big.

Factors associated with mother to child HIV transmission of HIV

A number of factors influence the risk of infection, particularly the viral load of the mother at birth: the higher the load, the higher the risk, 9 that’s why provision of ARV therapy is very important in order to reduce the viral load in these mothers and in the long run minimize the chances of MTCT of HIV.

Vaginal delivery has been found to be associated with increased chance of transmission of HIV from the mother to the child. Elective caesarian sections have proved to be protective against MTCT of HIV.

Poor obstetric practices such as early rapture of membranes, frequent vaginal examinations are also thought to increase the chances of MTCT of HIV

Breastfeeding is associated with a 10-20% chance of transmission of HIV from the mother to the infant. Under the current socio-economic trends in sub-Saharan Africa, most HIV positive mother are left with breast feeding as the only ‘safe ‘ and affordable option. A number of studies have shown that the protective effect of the various drug regimens is diminished when babies continue to be exposed to HIV through breastfeeding.10 This underlines the substantial risk of HIV transmission during breastfeeding which can greatly erode the short-term benefit of drugs to prevent MTCT of HIV.

Up to 20% of infants born to HIV-positive mothers may acquire HIV through breastfeeding. An HIV-positive mother should be counseled on the risks and benefits of different infant feeding options and should be helped to select the most suitable option for her situation. The use of infant formula can be problematic, and it may be neither feasible nor safe. However, breastfeeding may cause the child to become HIV positive, which may also result in illness and death.

The use of infant formula means the baby is not receiving the special vitamins, nutrients and protective agents found in breast milk. And the cost of infant formula often puts it beyond the reach of poor families in resource poor countries, even when the products are widely available. Many women also lack access to the knowledge, potable water and fuel needed to prepare replacement feeds safely, or simply have no time to prepare them. If used incorrectly - mixed with unsafe water, for example, or over-diluted - a breast milk substitute can cause infections, malnutrition and even death. Furthermore, if a mother chooses not to breastfeed in settings where breastfeeding is the norm, this may draw attention to her HIV status and invite discrimination, violence or abandonment by her family and community.

For HIV-positive women who choose to breastfeed, exclusive breastfeeding (as opposed to "mixed feeding" - breastfeeding mixed with bottle feeding of water or formula, or providing other foods) is recommended for the first months of an infant's life, and should be discontinued once an alternative form of feeding becomes feasible. This is because mixed feeding may increase the risk of HIV infection. Indirect evidence suggests that keeping the period of transition from exclusive breastfeeding to alternative feeding as short as possible may reduce that risk. Unfortunately, the best duration for this is not yet known and may vary according to the infant's age and/or the environment.11

Antiretroviral therapy for PMTCT of HIV

It was first found that the antiretroviral zidovudine could reduce MTCT over ten years ago12. Since then new drugs and drug combinations have been developed. Currently, there are many different drug regimens available and their use depends on a number of factors, including cost. The regimens can be divided into those that are used as part of longer-term treatment for the mother (long-term treatments) and those that are used only to prevent MTCT (short course treatments).

The most basic short course regimen is single dose nevirapine. Between 1997 and 1999 the HIVNET 012 study in Uganda found that single dose nevirapine given to the mother at the onset of labour and to the baby after delivery greatly reduced MTCT rates13. It is easy to administer and affordable ($4/ £2.50)14 particularly in Sub-Saharan Africa where resources are limited.

The biggest concern about the use of single dose nevirapine is resistance. Studies have found that single dose nevirapine can compromise a subsequent response to ART with nevirapine or efavirenz (a related drug) 15. This could have serious consequences for future antiretroviral treatment of mothers and infants using nevirapine or efavirenz and for preventing MTCT by using nevirapine in future pregnancies. There is also evidence that if a mother develops nevirapine resistant HIV, this can be passed through breast milk to her baby16.

Because of these concerns, there is now a general agreement that, single dose nevirapine should only be used when no alternative MTCT drug regimen is available. If possible, nevirapine should be used in combination with other drug(s) to prevent resistance problems and decrease MTCT rates even further.17 However, nevirapine is the only single dose ARV drug available to prevent MTCT. Other "short course" treatments require women to take ARV drugs  during and after pregnancy as well as during labour and delivery. This means they are much more expensive and difficult to implement in resource poor settings, compared to nevirapine that can be used with little or no medical supervision at all. So, for now, single dose nevirapine remains the best choice for preventing MTCT in regions where medical resources are limited such as sub-Saharan Africa.

One example of a longer "short-course" regimen is the combination of AZT and 3TC during labour and AZT and 3TC for one week postpartum for mother and infant. Another is AZT from 28 weeks of pregnancy plus single dose nevirapine at the onset of labour for the mother and a single dose of nevirapine for the infant within 72 hours of birth plus one week of AZT. This particular regimen appears to be almost as effective as triple combination anti retroviral therapy (ART) in reducing MTCT, as used in western countries.18

In western countries the recommended treatment regimen for preventing MTCT is triple combination therapy that includes AZT. As well as preventing MTCT, this treats the mother's HIV too. Women who are diagnosed as HIV positive during pregnancy may choose to start ART after the first trimester to reduce the risk of any possible side effects from the antiretroviral drugs.19

The major criticism of current PMTCT programs in sub-Saharan Africa is that; they are only focusing on prevention of HIV transmission from HIV infected women to their infants and hardly anything being done about the mothers HIV status. Preventing children from becoming infected is clearly important, but the exclusive focus on preventing infection in the child may be missing the point. If the mother is not cared for, becomes sick and dies, the child suffers – HIV infected or not. In sub-Saharan Africa, death of a mother is a high risk factor for child mortality. It is therefore important to keep the mother healthy. This will not only benefit the child and the family unit but will go a long way in preventing the massive growth of orphans in sub-Saharan Africa.

International initiatives to prevent mother to child transmission of HIV

There are a number of large-scale international initiatives to prevent MTCT of HIV. These include:

  1. President Bush's International Mother and Child HIV Prevention Initiative, now included in, President's Emergency Plan for AIDS Relief (PEPFAR)
  2. USAID's Efforts to Prevent Mother-to-Child Transmission of HIV21
  3. The Elizabeth Glaser Paediatric AIDS Foundation Call to Action Project22
  4. The UN Interagency Task Team on MTCT
  5. MTCT-Plus

With such support and efforts from these various organizations, there certainly hope for the developing world in the struggle to avert the problem of MTCT of HIV.

President Bush's International Mother and Child HIV Prevention Initiative

On June 19th 2002, President Bush announced a new $500 million International Mother and Child HIV Prevention Initiative to prevent the transmission of HIV from mothers to infants and to improve health care delivery in Africa and the Caribbean.

Through a combination of improving care and drug treatment and building healthcare delivery capacity, the initiative has the target of reaching up to one million women annually and reducing MTCT by 40% within 5 years or less in twelve African countries and the Caribbean.

Between October 2002 and March 2004 the US government provided $143 million. From FY 2005 both funding and activity are to be included in the President's Emergency Plan for AIDS Relief (PEPFAR). PEPFAR intends to rapidly expand the programs started by the International Mother and Child HIV Prevention Initiative by:

  • Scaling up existing MTCT programs by rapidly mobilizing resources.
  • Providing technical assistance and expanded training for health care providers.
  • Strengthening the referral links among health care professionals.
  • Ensuring the effective supply chain management of the range of MTCT-related products and equipment.

·        Expanding MTCT programs to include HIV treatment for HIV infected mothers and other members of the child's immediate family.20

USAID’s primary MTCT interventions

Improvement of antenatal services—USAID-supported sites are improving antenatal services—including voluntary counseling and testing—by training health workers and counselors, upgrading medical facilities, and providing HIV test kits. Community outreach workers are integral to reaching women and their families in areas underserved by traditional medical facilities.

Short-course antiretroviral prophylaxis for HIV-infected pregnant women—USAID currently funds the provision of antiretroviral drugs to reduce mother-to-child transmission, which studies have shown can reduce infection rates in newborn babies by 20 to 50 percent.

Support for safe infant feeding practices—safe infant feeding is one of the most complex aspects of MTCT prevention. In most developing countries, the majority of women do not know their HIV status and safe, affordable, and culturally acceptable alternatives to breastfeeding are limited. USAID funded MTCT programs provide HIV-positive women with information and support to help them make informed decisions about how to feed their babies.

Strengthening health, family planning, and safe motherhood programs— over the past 20 years USAID family planning programs have strengthened health systems to support safe motherhood. This includes improving obstetrical practices in order to reduce MTCT during delivery. Additionally, health counseling and safe, effective contraception can help women practice safer sex and prevent unintended pregnancies, potentially reducing the number of HIV-infected children.

For example in Uganda—The U.S. government strategy is to support the Ministry of Health in the scale-up of the national MTCT program through the identification of critical gaps and challenges. U.S. government efforts have identified and facilitated partnerships with private providers, non-governmental organizations and faith-based organizations to assist the ministry in this process. To accomplish this, USAID and CDC have focused on strengthening the capacity of the national MTCT program to lead, monitor, evaluate, and to improve capacity in training, staffing, counseling, behavior change communications, laboratory infrastructure, facilitating community outreach and mobilization, and strengthening the logistics and delivery system for MTCT-related commodities.

PMTCT-Plus

The PMTCT-Plus Initiative was started as a response to the UN Secretary General Kofi Annan’s “call for action” in 2001 to increase access to HIV/AIDS care and treatment in resource poor settings. The initiative expands on the MTCT model and recognizes that care and support is needed not just for the infants but also for their families. The “Plus” refers to the addition of the family-centered care and treatment. The program offers antiretroviral therapy, family focused counseling, preventive care, psychosocial support, and patient education in seven countries in Africa, with a number of additional countries set to join. This is encouraging because mother and father plus any other HIV+ children they have will receive ART under this program. This will improve the family’s general quality of life and improve survival with HIV/AIDS. There is a ray of hope for sub-Saharan Africa.

Lack of resources and capacity to upscale

In sub-Saharan Africa, limited human as well as financial resources represent major barriers to up scaling PMTCT programs. Human resources required for VCT and for administering antiretroviral drugs remain the highest cost, and in a number of sub-Saharan countries necessary financial and human resources are simply not available. As mentioned above, financial resources for up scaling PMTCT programs are increasingly becoming available. Although still insufficient the biggest challenge to African governments is now likely to be human and health system capacity to deliver the programs and services (particularly with the addition of PMTCT-Plus), as well as capacity to absorb the additional financial resources into public budgets and spending frame works. Therefore increased political commitment and leadership is required for the success of these programs.

Barriers to service uptake

Reasons identified for low uptake of available services include: denial of HIV infection, opposition from male partners, women’s fear of disclosure of HIV status to their partner – fear of being ‘found out’ if taking drugs or not breastfeeding, concern about taking drugs in pregnancy, not returning for checkups in the month before delivery, delivering at home or with the traditional birth attendants and premature delivery before treatment can be given.

Overcoming the barriers

Strategies for overcoming these barriers include;

·        Involvement of the male partner and the wider family in PMTCT programs. The criticism of PMTCT services is that they are too female focused and this has greatly limited the effectiveness and progress of these programs.

·        Intensifying education on infant feeding practices in order to address the low adherence to the recommended infant feeding practices for HIV positive mothers

·        Intensifying general community education and mobilization as a way of averting the stigma associated with HIV/AIDS

·        Support for HIV positive women who deliver at home is required if uptake of ART is to increase

·        Ensuring confidentiality and providing PMTCT services in a way that maximizes privacy.

·        Involving the family and community in designing appropriate service delivery as well as increasing demand for services.

 

Ethical concerns

 

The many difficult choices that have to be made center on the critical issue of who gets access to life saving services and why? These ethical dilemmas involve choices that will affect the life and death of millions of people in Africa. Human rights, law and ethics provide guidance to expanding services in a just and equitable manner. In resource poor settings, such as sub-Saharan Africa, this remains a challenge.

 

More information?

For more information regarding MTCT of HIV in sub-Saharan Africa these three websites are a great resource.

www.avert.org

www.changeproject.org

www.uneca.org

 

 

References

 

UNAIDS (2004): Report of the global AIDS epidemic. UNAIDS, Geneva.

 

UNAIDS (2004): State of the World’s children. UNICEF, New York.

 

WHO/ UNAIDS (2004): Consultation on  Equitable Access to Treatment and care for HIV/AIDS. Summary of issues and Discussion. WHO/ UNAIDS, Geneva.

 

WHO (2004): Anti-retroviral drugs and the prevention of mother-to-child transmission of HIV infection in resource constrained settings. Recommendations for use. 2004 Revision. WHO, Geneva.

 

Rutenberg et al, 2003: Evaluation of the United Nations-supported pilot projects for the prevention of mother-to-child transmission of HIV. Overview of findings.Population council/UNICEF, New York.

 

Commission on HIV/AIDS and Governance in Africa (2004); Mother-to-child Transmission Plus: Mitigation strategies for Africa. Economic commission for Africa. Addis Ababa.

 

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20. The President's Emergency Plan for AIDS Relief Annual Report on PMTCT of the HIV Infection, June 2004: www.state.gov/s/gac/rl/or/33896.htm

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22. ‘The Foundation Takes Action' The Elizabeth Glaser Foundation: www.pedaids.org/glob_calltoaction.html