Around 33 million people had the AIDS virus in 2007. The majority lived in Sub-Saharan Africa, according to the latest UN figures. One of the reasons so many people die in poorer countries is the cost of drugs.

The number of people living with HIV worldwide declined in 2007, according the United Nations Program on HIV/AIDS and the World Health Organization. The number of people dying of AIDS, living with AIDS, or newly infected start slowing in 2000 and either head downward or level off in 2007. The overall global declines were partly attributed to strong treatment and prevention programs, Paul De Lay, director of evidence monitoring and policy for UNAIDS said.

But with more than 6,800 new infections and over 5,700 deaths each day due to AIDS, researchers decided to expand their efforts in order to significantly reduce the impact of AIDS worldwide. 

The life expectancy of people infected with HIV in developed countries taking antiviral therapy has risen with no less than 13 years. Mortality among them had decreased by almost 40 percent, statistics show.

Researchers and people interested in this issue gathered in Mexico City to participate at the biennial International AIDS Conference, which goal is to transform the search for a vaccine into a global effort.

Previous vaccines contained a common cold virus loaded with copies of HIV genes. Researchers hoped that exposure to the genes would prompt an immune response in the body so that cells containing HIV virus would be recognized and destroyed. Vaccines can, however, help boost the immune system of those already infected, helping them fight the virus and extending their lifetime.

But the number of the new drugs beginning clinical trials has declined and the search for an HIV vaccine seems to be a slow process. One of the reasons it is so difficult to develop a vaccine is that the virus mutates and researchers have to change the vaccine every year.