Prevention of MTCT: Interventions

UNICEF's activities to control the HIV/AIDS epidemic

Recent research has shown that a range of interventions can reduce the risk of mother to child transmission of HIV/AIDS by up to 50 per cent. The primary effort is being directed to trying to prevent HIV/AIDS infection in women, young women in particular. In addition, three key interventions are being used to help to prevent mother to child transmission of HIV:

• Voluntary and confidential counselling and testing, particularly of pregnant women, can reduce the risk of mother to child transmission (MTCT) as well prevent subsequent sexual transmission of HIV/AIDS. HIV positive women need counselling in order to be able to make informed decisions about their own as well as their families' futures and about infant feeding options. Women testing HIV negative need to be counselled about preventive measures including safe sexual behaviour.
• Providing antiretroviral drugs to HIV positive pregnant women and ensuring safe delivery procedures can reduce risk of transmission at delivery. AZT, administered from 36 weeks gestation through labour until delivery, or a single dose of nevirapine given during labour and to the baby within three days of birth, are generally safe and can substantially reduce the risk of a mother transmitting HIV to her child. Both are on the WHO list of essential drugs.
• Counselling regarding infant feeding options can also reduce the risk of transmitting HIV from mother to child. Though HIV can be transmitted through breastfeeding, breastfeeding may nevertheless be the optimal choice a mother can make in certain situations about how to feed her infant. Counselling provides women with knowledge about the risks, benefits and costs of the various feeding alternatives, including breastfeeding, so that the mother can make her own informed decision about how best and most safely to feed her newborn child.

Voluntary and Confidential Counselling and Testing (VCCT) Access to information and to HIV testing and counselling constitutes a fundamental human right. It is critical for women to be aware of their HIV status as their actions impact on the health and well being of their families and can prevent subsequent sexual transmission. Counselling provides women with information about their condition, whether positive or negative, so they can make informed choices. And it educates pregnant women about what they can do to prevent mother to child transmission. In countries with high HIV infection rates, UNICEF supports the introduction of voluntary and confidential counselling and testing as a prerequisite for the implementation of other interventions to reduce HIV transmission. The most effective interventions to reduce transmission from mother to child depend on the mother knowing her HIV status and subsequently receiving the necessary counselling and information if she tests positive. Voluntary and confidential counselling and testing services, therefore, need to be widely available and acceptable to adolescent girls, pregnant women and their partners. In view of women's risks of stigma, violence and loss of family and livelihood, confidentiality is an essential element of counselling, testing and of all other services for HIV positive women. The goal is that within two years, 70 per cent of all women attending antenatal clinics will have access to voluntary and confidential counselling and testing. If positive, pregnant women need access to counselling concerning their own futures as well as about infant feeding options to help them weigh the benefits and risks of breastfeeding and alternative feeding methods. HIV positive women should be supported to make their own decisions and to carry out their choice of infant feeding method. The majority of women, however, test HIV negative. For them and their partners, counselling provides important information about measures, including safe sexual practices, critical to helping them remain HIV negative. HIV voluntary confidential counselling and testing in relation to pregnancy and other reproductive health services often proves to be a valuable entry point for the provision of VCCT to the wider community of women, their partners, and young people. A growing number of studies have indicated that voluntary confidential counselling and testing can contribute to an increase in an individual's safe behaviour-and reduce fear, stigma, and discrimination at the community level. UNICEF strongly believes that access to information, and to testing and counselling, constitutes a fundamental human right. Knowing one's serostatus (HIV+ or HIV-) is an individual's right, if s/he chooses to be tested. Therefore, effective strategies to ensure access to testing and counselling services must be a priority. A number of hurdles still need to be overcome to achieve effective voluntary and confidential counselling and testing. The cost of these services remains high in most countries. There is also a dearth of well trained counsellors and an over-reliance on volunteers in many areas. Fear of stigma and discrimination among women and adolescent girls regarding a potentially positive HIV status still inhibits adequate use of VCCT services even where they are available. The quality of services must also be improved to boost use.

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Antiretroviral Drugs Antiretroviral drugs reduce mother to child transmission when started before, during delivery, but even if taken within 48 hours after delivery. Antiretrovirals work mainly through two mechanisms:

1. Reducing the viral load in the mother so a lesser quantity of virus is transmitted to the infant.
2. Preventing the virus from "fixating" itself in the child, also called "post-exposure prophylaxis."

Risk reduction through antiretroviral therapy given in the antenatal period and during delivery persists through the breastfeeding period. Continuing antiretrovirals in breastfed children is a promising new intervention likely to be effective in reducing transmission of HIV through breastmilk. Although some side effects have been observed, antiretrovirals are generally safe with the benefits of the drugs outweigh the risk of side effects. These drugs continue to be monitored. UNICEF-assisted MTCT prevention programmes use the drug AZT (sometimes called zidovudine or ZDV) and have adopted the protocol initially developed in Thailand in 1997. This short regimen gave 300 mg AZT orally twice daily from 36 weeks gestation until the onset of labour and 300 mg every three hours from the onset of labour until delivery. This regimen decreased mother to child HIV-1 transmission by 37-38 per cent in breastfeeding populations after 18 months and by 50 per cent in non-breastfeeding populations. Botswana used a modified regimen of antiretroviral therapy at 34 weeks and administered AZT syrup to the baby for four weeks.

In January 1999, the results of a major research study in Uganda became available which showed that another drug, nevirapine, could achieve an equivalent reduction of transmission with only a single dose to the mother during labour and a single dose to the baby within three days of birth. The nevirapine regimen costs about $4.00 for each mother /child pair. The current consensus of the UN agencies is that nevirapine is one of the suitable regimens for decreasing the risk of MTCT of HIV/AIDS, especially for women who detect their HIV positive status or arrive at the health facility too late in the pregnancy to benefit from the AZT regimen. The new single dose nevirapine regimen substantially lowers the cost barrier that has kept many countries from adopting drug strategies to prevent perinatal transmission. Long term follow-up of both the mothers and babies remains a high priority to assess any late drug toxicities as well as long term survival. Research results may indicate that a combination of nevirapine with AZT or other drugs may be more effective. Findings will have important implications for the provision of interventions to prevent MTCT of HIV in developing countries. Both AZT and nevirapine are on the WHO List of Essential Drugs for MTCT. The low cost of nevirapine does not, however, justify mass treatment without individual counselling and testing. The side effects of nevirapine have not been fully established yet. Additionally, blanketing populations with this drug can create resistance to it

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Infant Feeding and HIV

Mothers are best placed to decide how to feed their infants, but to make an informed choice, they need counselling to know the advantages, risks, benefits and costs associated with all infant feeding options. Trained counsellors can also support mothers as they make and carry out their own decisions. The UNICEF/WHO/UNAIDS policy guidelines regarding infant feeding accommodate all infant feeding options for mothers with HIV. Furthermore, they support a fully informed choice based on all available information and advocating that mothers be provided with new and better information as it becomes available.

Since there is a possibility of transmitting HIV through breastfeeding, replacement feeding is an option for mothers. If an HIV-infected mother has access to an adequate supply of breastmilk substitutes, knows how to use them, has access to fuel and clean water and the time to prepare breastmilk substitutes safely, refraining from breastfeeding will reduce the risk of transmitting HIV through breastfeeding. In countries where families live in poverty, have limited education and poor access to the resources required to provide safe feeding alternatives to breastfeeding, including counselling, however, the risk of death from diarrhoea, respiratory, and other infections associated with replacement feeding can be as great or greater than the risk of transmitting HIV through breastfeeding. As a general principle, the guidelines advocate that in all populations, irrespective of HIV infection rates, breastfeeding should be protected, promoted and supported and that HIV positive mothers who choose to breastfeed should be given full support for their decisions. Women who do not wish to be tested for HIV and those who have tested negative should be encouraged to breastfeed. If an HIV positive mother chooses to breastfeed, she should do so exclusively. Combining breastfeeding and replacement feeding is inadvisable because partial breastfeeding supplemented with water, formula or other drinks appears to elevate health risks, including HIV transmission, possibly because these supplements can damage the infant's gut and make it easier for viruses to cross the intestinal mucosa.

The consensus of ongoing research to determine mechanisms of HIV transmission from an infected mother to her child is that the risk of transmission will be reduced if the duration of breastfeeding is limited. The exclusively breastfeeding mother, therefore, may wish to stop breastfeeding completely at 4 to 6 months to prevent late postnatal MTCT. However, at the present time, the evidence is not strong enough to make a firm recommendation on a specific cut-off age when breastfeeding should completely stop. Recommendations will be kept under review as knowledge in this area increases.