"[This is] one of the greatest public health achievements possible," WHO director general, Margaret Chan, told the press. And the best part is that it was brought about by relatively simple strategies: namely, better testing and treatment of expectant parents, and providing HIV- and syphilis-positive mothers with options to protect their babies, such as bottle-feeding and C-sections.
What Cuba has done differently is integrate these treatments into accessible and affordable universal healthcare, so that they've become a normal part of treatment for all pregnant women.
"This is a major victory in our long fight against HIV and sexually transmitted infections, and an important step towards having an AIDS-free generation," said Chan. "It shows that ending the AIDS epidemic is possible."
Around the world each year, an estimated 1.4 million HIV-positive women become pregnant. Without any intervention, they have a 15 to 45 percent chance of passing the virus onto their children while they're in the womb, as well as during labour, delivery and breastfeeding. But that risk drops to just 1 percent if both mother and child receive antiretrovirals.
The rate of syphilis isn't far behind, with around 1 million expecting mothers worldwide each year infected. Similarly, the risk of transmission is greatly reduced by treating the mother with penicillin during pregnancy.
In fact, the hard part about stopping mothers from passing the diseases on has simply been giving women access to these treatments, which Cuba has now done.
WHO counts a country as having eliminated mother-to-baby transmissions when the rate of children born with HIV or syphilis is so low that it "no longer constitutes a public health problem".
Basically that means a country needs to have less than 50 cases of HIV and syphilis per 100,000 live births, maintained for at least a year, as well as at least 95 percent of pregnant women being tested for the diseases, and 95 percent of those who test positive receiving proper treatment.
WHO reports that Cuba has now met those targets, with only two babies being born with HIV in 2013, and five with congenital syphilis.
But it's not the only country making big improvements in this area, and Chan now expects others to follow Cuba's lead and seek validation that they've ended mother-to-baby transmission. Worldwide, childhood infection rates are quickly dropping, with just 240,000 children born with HIV in 2014 - nearly half the 2009 amount.
Still, we have a long way to go before WHO reaches its global target of just 40,000 new child infections per year, and Cuba has shown that better healthcare can help get us there.
"Cuba’s success demonstrates that universal access and universal health coverage are feasible and indeed are the key to success, even against challenges as daunting as HIV," said Carissa Etienne, director of the Pan American Health Organisation. "Cuba’s achievement today provides inspiration for other countries to advance towards elimination of mother-to-child transmission of HIV and syphilis."