I work in the bad news business. As an aid worker if I'm not busy with natural disasters, it's civil war, if it's not civil war it's a terrible epidemic. But I want to write about something you don't see often - good news, even rarer in that it comes from poor countries.

This week new data will show a huge reduction in measles deaths worldwide - saving millions of children's lives.

The breakthrough has been announced by the Measles Initiative, a partnership of the United Nations Children's Fund, the World Health Organisation and the American Red Cross. In the past five years their work has resulted in measles deaths plummeting by 60 per cent - saving about 7.5 million lives.

Measles is the most contagious disease known to humanity and for children in poor countries it's one of the most deadly. It is also preventable by vaccination, and a cheap and safe inoculation has been available since the 1960s.

Dennis McKinlay, Unicef New Zealand's executive director, says: "Just two doses of an inexpensive, safe, and available measles vaccine can prevent most, if not all, measles deaths."

Each year measles kills 1 million children, most of them under 5. Survivors are often left with lifelong disabilities including blindness and brain damage.

These figures are even more shocking because effective immunisation, which includes vaccine and safe injection equipment, costs just $1 and has been available for more than 30 years.

Measles is a viral disease spread by infected droplets during sneezing and coughing, and by touching contaminated objects. It causes fever and a rash, and can lead to convulsions, pneumonia, bronchitis and, for many poor children, death.

In cramped, insanitary places like refugee camps, measles can kill a child in less than five hours. During the Pakistan earthquake, my Unicef colleagues and I were literally running from camp to camp with vaccines trying to move faster than the virus.

In industrialised countries the disease is seldom fatal because infected children eat well and have proper medical care, are fully vaccinated and live in sanitary conditions.

However, this is often not the case in many parts of Africa and Asia which lack good healthcare infrastructure. The WHO and Unicef say poor immunisation systems in developing countries are the main reason for high numbers of deaths from measles.

A baby girl born in sub-Saharan Africa faces a 22 per cent risk of death before she turns 15. In China the risk is less than 5 per cent and in industrialised countries just 1.1 per cent.