In a plenary session of the Sixth International Conference on AIDS in Asia and the Pacific (ICAAP) Dr Susan Paxton of Melbourne University, who is herself HIV positive and a mother, reviewed the issues raised by the continuing transmission of HIV from mothers to their babies. (Her talk is now accessible as a webcast, following the link to the conference website.) A number of sessions and posters concerned clinical trials and pilot programmes, some of which are now being transformed into national programmes, to prevent HIV and AIDS among children.
Dr Paxton spoke very powerfully of the experience of positive women who had foregone childbearing or in some cases been forbidden to have children, through forced sterilisation. Many women were terrified of transmitting the virus and were feeding with substitutes even when this in itself presented a major risk to their children and was very hard for them to sustain.
In Australia, for the last five years, according to Dr Paxton, there has not been an HIV positive child born to a woman whose HIV status was known during the pregnancy. At other conference sessions, it was reported that Malaysia has a full-scale national programme to prevent mother-to-child transmission. Thailand has a rapidly expanding programme which has already achieved a reduction in AIDS among children, in addition to the reduction achieved through prevention of HIV transmission among adults. Cambodia, Myanmar, Vietnam and Papua New Guinea among other countries are set to follow, with pilot programmes either in place or about to start, although the healthcare infrastructure in these countries doesn't match the extensive network of clinics that exists in Thailand. China and India both have pilot programmes in some areas, although the challenge of setting up full-scale national provision in such large countries, when access to antenatal care is limited, is immense.
The Thai programme, which began with pilot provision in Northern Thailand in 1996, aims to offer AZT monotherapy for at least 4 weeks before birth to the mother (if she would not otherwise be receiving antiviral treatment) and this is followed by one week's treatment for the baby. If the mother received less than 4 weeks' treatment before the birth, then treatment for the baby is extended to six weeks.
The two-dose regimen of nevirapine that is now being provided in a number of African countries, and which is considered more practical where antenatal care is very limited, is considered inferior in Thailand, although clinical trials are planned in which it will be added to the AZT regime described.
One of the major benefits of instituting these programmes, which have to be provided through mainstream clinical services, is to transform the attitude of healthcare workers towards people with HIV. As training and systems are put in place, staff have come to take pride in their ability to save lives and support the families affected by the disease.
As Dr Paxton observed, interventions that depend on women knowing their HIV status have severe limitations. She estimated that they could only prevent 25 per cent of transmissions. There also continues to be a serious ethical problem when services are able to prevent HIV transmission to babies but are unable to provide treatment for the babies' parents. Limiting factors included continuing difficulties in providing counselling and testing, lack of access to antenatal care, and continuing discrimination and abuse suffered by women who tested positive.
Throughout the conference, there was recognition of the need to learn from mistakes made in parts of Africa where testing of mothers but not their male partners led to a perception that women were the “source” of HIV and AIDS in families.
This is an issue and a responsibility for men as well as women. It was therefore encouraging to hear that the programmes now being scaled up in Thailand are seeing husbands and male partners of pregnant women attending clinics for counselling and testing. The strongest – some would say the only – evidence for voluntary counselling and testing as an HIV prevention strategy is where couples test together. If a man is positive and his pregnant female partner is negative, his concern to protect his child may be a powerful motivator to protect his female partner too. Condom use, STD treatment, and commitment by men not to have other sexual relationships were all critical. The “Stepping Stones” approach used in Southern Africa to challenge sex roles and enable communities to put an end to violence against women had profound effects where she had seen it implemented in Zambia. This, rather than medical interventions, could get closer to the root of the problems.
Breastmilk transmission infects around 15 per cent of breastfed children born to HIV positive women (which might be reduced through exclusive breastfeeding). This risk doubles if the woman is infected during the period when she is breastfeeding. This information needs to be communicated to fathers, to encourage them to take responsibility for the health of their children.
So, should we be talking about parent-to-child transmission or mother-to-child transmission? The emerging consensus is that for the global epidemic, we must talk about both.