At least 33 million people are alive with HIV and perhaps another 43 million have already perished from Aids. Aids is the biggest health problem the world has ever faced.
Having just marked World Aids Day once again, it's worth us each stopping to consider the scale of this tragic disease - and to consider what we as individuals might be able to do to alleviate the problem.
But when the headlines reflect such a massive worldwide problem, it's easy to feel overwhelmed; it's easy to raise our hands in despair and say, "What can I possibly do to alleviate a problem that's become so huge?"
The World Health Organisation's 2004 report said that: "HIV/Aids may not be curable, but it is certainly preventable and treatable."
At one point Uganda had one of the highest rates of infection in the world. The Ugandans have a saying: "one plus one soon makes a bundle." Every individual can make a difference - so too can organisations, community groups and churches.
Today, Uganda's infection rate has dropped in no small part because of a grass-roots movement that encourages abstinence and faithfulness. Christian churches have been at the forefront of this movement. They've also been on the front line of providing Aids care and supporting Aids orphans.
As individuals and organisations, we can lobby local members of Parliament for more funding for Aids research or Aids care.
We can also talk to them about stopping the international sex trade, which leaves so many people - in particular children - vulnerable to the spread of Aids.
More than $10 billion is needed every year for Aids prevention and treatment in poor countries - and the cost keeps growing.
Rich governments need to invest more in distributing treatments to poorer neighbours.
We can also pressure drug companies to share their know-how with the poor.
Whilst there is as yet no medical cure for Aids there have been some positive signs with the development of anti-retroviral drugs. These drugs have some pretty uncomfortable side effects, but at least they stop HIV from reproducing inside the body; they give the body some breathing space to fight back.
But anti-retrovirals are still not available to everyone who needs their help, especially the poorest of the poor. Drug companies see no profit margin in giving their products away.
We need to bring pressure to bear so that drug companies look beyond the bottom line, cutting their margins and in some cases waiving their profits altogether, in the interests of being humane.
