"In [the] 25 years since the first case was reported, AIDS has changed the world," he said. "It has killed 25 million people and infected 40 million more. It has inflicted the single greatest reversal in [the] history of human development. In other words, it has become the greatest challenge of our generation."
Annan was speaking at a public gathering in New York on November 30, just ahead of today's anniversary.
"Today in developing countries, one in every four adults who needs treatment to live has access to that treatment. That number is far too low. But it is far better than the less than one in 10 children who need treatment to live."
Improvement In Last Decade
Annan said that during much of the first 15 years in which HIV -- the virus that causes AIDS -- spread worldwide, societies were "in denial."
But over the past 10 years, he said, attitudes have changed and more and more resources are being committed to curb the disease.
But he said, the effort is still not enough.
"Financial resources are being committed like never before, people have access to antiretroviral treatment like never before, and several countries are managing to fight the spread like never before," Annan said. "But the spread continues, and we need to mobilize like never before."
In a formal written message to commemorate World AIDS Day, Annan said that success in defeating AIDS requires a personal commitment by people at every level of society.
New Infections Continue
He called on national leaders, politicians, and every person to protect others against the AIDS threat.
Tens of millions of people worldwide have either died of AIDS or are infected with HIV. UNAIDS, the UN agency coordinating the fight against AIDS, estimates there will be 4.3 million new infections this year.
About 65 percent of the new cases are in sub-Saharan Africa.
But UNAIDS says some 270,000 people were also newly infected with HIV this year in Eastern Europe and Central Asia, bringing to an estimated 1.7 million the number of people living with HIV in these regions.
Children are increasingly among the victims.
Youth Infections Increase
Experts estimate that more than 2 million children around the world are living with AIDS, and that almost half of the new infections occur among young people aged 15 to 24.
Former U.S. President Bill Clinton, an advocate for helping children infected with AIDS, called attention to the problem in New Delhi on November 30.
"Still, with all the progress we have made [in the global fight against AIDS], not much has been done for children who are living with HIV through no fault of their own," he said. "Today in developing countries, one in every four adults who needs treatment to live has access to that treatment. That number is far too low. But it is far better than the less than one in 10 children who need treatment to live."
Clinton said on November 30 that his charitable foundation has reached a deal with two Indian companies to supply 19 antiretroviral drugs to children in that country at one-half of their usual cost.