Child deaths from measles have fallen by 60% following a massive global vaccination campaign.
Mass vaccination is key to success
A study in The Lancet confirms that hundreds of thousands of lives have been saved since 1999, surpassing a target of halving deaths by 2005.
In Africa, efforts by national governments and health agencies have cut mortality by three-quarters.
Now scientists are considering more ambitious targets, and perhaps even the complete eradication of the disease.
Measles is not a major killer in the western world, with the vast majority of children vaccinated against the disease at about two years old.
In less developed countries however, the death toll is much higher, as children are far more likely to die from the complications of the disease such as encephalitis, pneumonia and diarrhoea.
In 1999 there were 875,000 deaths worldwide, the majority in Africa.
This prompted the creation of the "Measles Initiative" in 2001, a joint campaign between organisations including the American Red Cross, Unicef and the World Health Organisation.
This worked with dozens of different governments to increase the numbers of children having the opportunity to be vaccinated early in life.
Between 1999 and 2005, more than 360 million children across the world received a measles jab as part of mass vaccination efforts.
The "coverage" - or proportion of children getting the first vaccination - has risen from 71% to 77%, say researchers.
In 2005 there were approximately 345,000 deaths from the disease.
The tumbling death rates in Africa have been greeted with delight by national governments.
Olanguena Awono, the Minister of Public Health of Cameroon, said: "We are winning the fight against measles, which has long killed, sickened and disabled our children."
Dr Julie Gerberding, director of the US Centers for Disease Control and Prevention, another partner in the project, said: "One of the clearest messages from this achievement is that with the right strategies and a strong partnership of committed governments and organisations, you can rapidly reduce child deaths in developing countries."
UNICEF Executive Director, Ann Veneman, added: "Immunising children is clearly saving lives. Reducing measles deaths by 60% in just six years is an incredible achievement."
The next target will be more difficult to achieve - a 90% reduction by 2010 from the death rate in 2000, mainly by making sure that children have the chance of a second dose of measles vaccine shortly after the first.
The study authors believe it may be possible to eradicate the disease altogether, but they said there appeared to be 'little appetite' for the effort required to achieve this.
Experts from the Children's Population Health Unit at Great Ormond Street Children's Hospital in London also doubted whether eradication was possible.
Helen Bedford and David Elliman said that the high infectivity of the virus meant that a vaccine coverage needed to be almost complete to eliminate it as a threat, and there would be difficulties reaching some vulnerable groups of children with a vaccine.