BANGKOK • Thailand has become the first Asian country to eliminate mother-to-child transmission of HIV, the World Health Organisation (WHO) said yesterday, a milestone in the fight against the disease.

The announcement is a boost for a generation of Thai health workers who have transformed the nation from one of Asia's most HIV-ravaged societies to a pin-up for how to effectively tackle the crisis.

Describing the elimination as a "remarkable achievement", the WHO said Thailand was "the first (country) with a large HIV epidemic to ensure an Aids-free generation".

Belarus and Armenia were also declared free of mother-to-baby HIV transmissions yesterday, but both nations have a much lower prevalence of the virus.

Previously, Cuba was the only other country to have eliminated mother-to-child transmission under the WHO's criteria back in July last year.

The global health body said Thailand's routine screening and universal free medication for pregnant women with HIV were crucial in stopping the virus from being passed to new generations.

If left untreated, mothers with HIV have a 15 to 45 per cent chance of transmitting the virus to their children during pregnancy, childbirth or while breastfeeding.

But taking antiretroviral drugs during pregnancy significantly reduces those chances to just over 1 per cent.

In 2000, Thailand became one of the first countries in the world to provide free antiretroviral medication to all pregnant women diagnosed with HIV.

Screening for the virus during pregnancy is also routine, even in the country's most remote areas, the WHO added.

According to Thai government figures, the number of babies born with HIV dropped from 1,000 in 2000 to just 85 last year, a large enough fall for the WHO to declare mother-to-child transmission over.

A small number of cases are taken into account as treatment with medicine is not 100 per cent effective.

It is a major turnaround for Thailand. The country went from 100,000 HIV cases in 1990 to more than a million three years later, fuelled in part by its huge sex trade.

Health workers initially struggled to persuade governments to act.

But an eventual push to distribute free condoms among sex workers throughout the late 1990s and the widespread rollout of antiretroviral drugs in the 2000s have seen huge success and won the country widespread praise.

"Thailand's progress shows how much can be achieved when science and medicine are underpinned by sustained political commitment," Unaids executive director Michel Sidibe said in a statement.

Each year, 1.4 million women living with HIV around the world become pregnant.

The number of children born with HIV was 400,000 in 2009. By 2013, the number was down to 240,000.

AGENCE FRANCE-PRESSE