Children with HIV and Aids in the developing world are half as likely as adults to get life-saving drugs. This means fewer than one in 10 of over two million children infected get anti-retroviral treatment (ARVs).
Phindile is not sure if her son is also infected
The BBC's Angus Crawford met three children living with the illness in Swaziland, which has the highest rate of infection in the world.
Nkhosibona is very shy. He sits in his mother's arms, wriggling and putting his head on her shoulder.
His father died of Aids three years ago and his mother Phindile is HIV-positive. But what she can't do, like thousands of others, is find out if her boy is infected too.
"I don't have money, the hospitals are too far, I have to go by bus," she says.
"There are many families here facing the same problem."
I ask her what happens to those children.
"We wait until they get ill and die," she says.
The first barrier to treatment is diagnosis. Just like Nkhosibona, more than 90% of those with HIV in the developing world don't know they have the disease.
Half of all children born with the illness will die before their fifth birthday.
"Children have been the missing face in the fight against HIV and Aids because they don't speak for themselves and they cannot be tested until they are over 18 months," says Pelucy Ntambirweki of the UN children's charity, Unicef, based in Swaziland.
Thembelani is wearing a bright yellow shirt covered in red pineapples and the word Hawaii.
The drugs are not always in a form children can take
When he sees us he runs to a small mud brick house surrounded by weeds.
His father Jeremiah comes out to greet us. He and his wife are both on ARVs but he doubts whether his son, who's also HIV-positive, will get the treatment.
"They want you to be very, very sick - be bed-ridden first," he said.
The journey to the clinic takes five hours by bus but they don't have enough money for the fare.
A second barrier to treatment is poverty, poor infrastructure and a lack of medical staff.
Pelucy says the chances of a child like Thembelani getting treatment "depend on who is taking care of him, how far he is from the clinic, and if there is access to the right medication".
Thanks to charities, governments and drugs firms those medicines are usually free to the poorest. But they are not always user-friendly.
Xolani is tiny. He is 12, but is the height of a five-year-old.
He proudly shows me his ARVs. "He has improved very, very much - tremendously health wise," says his father Mangaliso.
That is because Xolani is taking adult drugs which are broken in half.
Many child victims of HIV and Aids die before they are five years old
Before he took bottles of syrups designed for children, but his father found it hard to get the dose right.
He gave his son three bottles, twice a day in a hut with no light. The markings on their one syringe rubbed off.
Xolani became more and more ill.
What doctors in Swaziland want are easy to use, fixed-dose combination drugs - they exist for adults but not yet here for children.
"Having a product that is one size fits all - no one is saying that's feasible," says Jon Pender, director of government affairs for GlaxoSmithKline, the largest pharmaceutical company in Europe.
They provide their ARVs at cost price to Africa and deny they are neglecting investment in child-friendly drugs.
"The tools are there to treat children but most mothers in Africa don't have access to any kind of health care systems at all," he says.
For Xolani, Thembelani and Nkhosibona, it is ultimately poverty which will decide whether they live or die.