Mother to child HIV transmission at record low in the UK

The rate of mother to child HIV transmission is at an all-time low in the UK, according to a paper published today in the journal AIDS.

The study examined over 12 000 pregnancies in women diagnosed with HIV before or during pregnancy and delivered in 2000-2011; there was a four-fold drop in the rate of mother to child transmissions, from 2.1% in 2000-2001 to 0.46% in 2010-2011.

Dr Claire Townsend (UCL Institute of Child Health) said: "Mother to child HIV transmission is now at the lowest level ever in the UK & Ireland, and as far as we're aware such low levels have never been reported on such a large scale."

The continued fall in transmission rates is thought to be due to a combination of factors including earlier initiation of antenatal combination antiretroviral therapy (cART) and an increase in the number of women already on cART when they conceive.

These new statistics are in line with the World Health Organisation's goal of virtual elimination of mother to child transmission by 2015. The dramatic fall in the transmission rate in the UK can also be attributed to a very high uptake of antenatal HIV screening, which is offered to all pregnant women, and a multi-disciplinary approach to the management of HIV positive pregnant women and their babies.

How common is mother-to-child transmission today?

In 2011, around 330,000 children under the age of 15 became infected with HIV and an estimated 230,000 died from AIDS.4 Almost all of these infections were as a result of mother-to-child transmission and among children living in sub-Saharan Africa.

However, mother-to-child transmission can be averted, and in high-income countries mother-to-child transmission has been almost completely eliminated as a result of effective voluntary testing and counselling services, access to antiretroviral therapy, safe delivery practices, and the widespread availability and safe use of breast-milk substitutes. Globally, since 1995, more than 350,000 children have avoided HIV infection due to these interventions. If these interventions were available and accessible to women worldwide, they could prevent thousands of children from becoming infected with HIV each year.

The study found that there was a marked decline in the proportion of diagnosed HIV-positive pregnant women who received no antenatal cART from 3.3% in 2000-2006 to 1% in 2007-2011 and an increase in the duration of treatment during pregnancy. A longer duration of treatment was significantly associated with reduced transmission risk.

The study also highlighted the extensive inequalities in the availability of interventions to prevent mother to child HIV transmission worldwide. In the UK 99% of diagnosed HIV positive pregnant women receive cART, whilst UNAIDS estimates that similar treatment regimes in West and Central Africa reach only 27%. The statistics within Europe also show a large gap in access to treatment with transmission rates as much as 4-10 times higher in some parts of Eastern Europe (0.46% transmission in the UK, compared to 2-4% in Russia and 4-5% in the Ukraine), where prevalence of HIV in pregnant women is higher and access to antiretroviral drugs more limited.