A Department of Health-backed scheme has proved hugely successful in preventing the transmission of HIV from pregnant women to their children. Nicole Matthews reports.
Aids claimed the lives of an estimated three million people in 2005 and there are currently 40 million living with HIV worldwide.
While sub-Saharan Africa is still the most severely affected region, HIV is spreading fastest in Asia and eastern Europe, according to a UN Aids report released in May this year.
If Aids is spreading at this rate, how then has Ireland managed to curtail the virus?
In 1998 the Rotunda Hospital in Dublin introduced a pilot study involving antenatal testing on mothers for HIV. Due to the success and high uptake of the screening, the Department of Health and Children decided to back the initiative and it was rolled out on a national basis in 1999.
"Ten years ago it was essentially more of a surveillance exercise," says David Moloney, a principal officer with the Department.
"Then it moved towards early detection, which is very important in tackling HIV and has a very high success rate when treated."
One way of combating the spread of HIV is by blocking its transmission from mother to infant during pregnancy through a combination of drugs known as antiretroviral treatment.
In Ireland last year, approximately 100 to 120 HIV-positive pregnant women received antiretroviral treatment and less than 1 per cent of their infants contracted HIV.
Without the treatment, between 15 and 40 per cent of the infants concerned would have been expected to contract the virus. In other words, instead of 35-50 babies being born in Ireland each year with HIV, one infant per year is born who will become HIV-positive.
Initially, the testing was offered on an opt-out basis, which led to an uptake of more than 95 per cent, but now screening of all maternity hospital patients is routine.
If a mother is diagnosed through the antenatal screening, antiretroviral treatment will start in her first trimester of pregnancy, usually at about 20 weeks.
When the virus is detected early, antiretroviral treatment has a very high success rate in reducing the viral load and preventing transmission of HIV to the unborn child.
Dr Karina Butler, consultant paediatrician and head of infectious diseases at Our Lady's Hospital for Sick Children Crumlin, believes that detecting HIV early in pregnancy is key to the success of preventing transmission to the baby.
"In some cases it can be too late, for example when a woman is 38 weeks and comes in for her first antenatal check up. Ideally, antiretroviral treatment should start at a minimum of six to eight weeks prior to delivery," says Dr Butler.
A programme is followed monitoring the progress in the mother and child. This is known as triple therapy, as it involves targeting the virus, suppressing it and giving a normal delivery.
If the treatment is not successful in reducing the mother's HIV viral levels, a Caesarean delivery will be offered to reduce the transmission rate.
Further treatment may take place post-delivery.
Dr Mary Cafferky, consultant microbiologist at the Rotunda Hospital, explains that there are important guidelines which mothers must follow.
"We will always treat the baby for the first four weeks of their life to reduce the viral load as much as possible. However, we also always recommend against breastfeeding as HIV can be transmitted through the mother's milk."
Dr Cafferky says cases in which HIV is transmitted from mother to child usually arise because the treatment was given too late "or for reasons unknown did not reduce the mother's viral load".
Although 90 per cent of the world's HIV-positive children live in sub-Saharan Africa, antiretroviral treatment is being introduced to the region slowly and belatedly.
As a result, many children are still contracting the virus during the birth process and through breastfeeding due to a lack of education.
Antiretroviral treatment is more cost-effective for all states in the long run as it is cheaper than dealing with the health consequences of allowing large numbers of children develop Aids.
The simple process of antenatal screening and antiretroviral treatment which has been operating in Ireland for the past eight years has proven to be hugely successful and could, if replicated elsewhere, help stem the paediatric Aids epidemic worldwide.
"Due to the forward-thinking in this country and support from the Department of Health, a number of babies have been successfully prevented from acquiring HIV in Ireland," says Dr Butler.