Global measles deaths have dropped by 60 percent, health authorities announced in a report Friday, and one senior official called it a "historic victory" for public health.

Nearly 7.5 million children were saved from dying of measles between 1999 and 2005, thanks to increased immunization campaigns, the World Health Organization said. More than 360 million children aged 9 months to 15 years were vaccinated against measles during that period.

Measles is one of the most infectious diseases that exists. Though it is no longer a major problem in the West, in poor countries, the disease can kill as many as 30 percent of the children it infects, particularly in those with weakened immune systems.

"This is a historic victory for global public health," said Dr. Margaret Chan, WHO's director-general. Health authorities had hoped to cut measles mortality rates in half by 2005, but found that they had exceeded that goal by 10 percent. In Africa, the results were even more striking: measles deaths fell by 75 percent on the continent.

"It's not very often that global health initiatives not only achieve their goals, but actually exceed their goals faster than expected," said Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention. The measles success achieved to date, Gerberding said, has encouraged the global community to aim even higher, as they set a new goal of reducing measles deaths by 90 percent by 2010.

According to Geneva-based WHO, the next phase of this initiative is projected to cost about $500 million, of which $150 million has already been committed.

In a study published Friday in the British medical journal The Lancet, WHO scientists estimated that the number of measles deaths fell from 873,000 in 1999 to 345,000 in 2005.

Because surveillance figures from countries are not available, WHO based its figures on a modeling system that estimates the number of measles cases based on coverage rates achieved during vaccination campaigns. Experts said the numbers should be reasonably accurate.

If the 2010 goal is met, health officials may then start considering whether it might be feasible to eradicate measles. Like smallpox and polio, an effective vaccine exists, making it a potential candidate for eradication.

Still, the problems plaguing polio, which was originally supposed to be eradicated by 2000, may undermine any proposed measles campaign.

"The continuing failure to meet the polio eradication goals will cast much skepticism and pessimism on any similar global venture for measles," said Dr. Samuel Katz, co-inventor of the measles vaccine. Katz is also an infectious diseases specialist at Duke University.

"Donor and participant fatigue take their toll," he said.

To date, the effort to eradicate polio has cost $4 billion. And while health officials are tantalizingly close to the finish line -- polio incidence has been cut by 99 percent -- it remains stubbornly endemic in Afghanistan, India, Nigeria and Pakistan.

Whether or not measles eradication will be attempted will depend largely on if the 2010 goal can be met.

"That will be another milestone to measure if elimination is possible," said Dr. Vance Dietz, chief of the global measles department at the CDC.

"It may be that by then, we are so far ahead that regardless of what's happened with polio, people will want to move ahead," he said.

The Measles Initiative was launched in 2001 to reduce measles deaths worldwide. Its major partners are the American Red Cross, the CDC, the U.N. Foundation, UNICEF and WHO.