Researchers warn against Merck's AIDS vaccine

More than a month after halting the HIV vaccine trials that involved the Merck & Co., Inc.'s investigational AIDS vaccine, the researchers have started warning hundreds of volunteers who took part in the trials that the vaccine might leave them more vulnerable to HIV infection.

Hopes of finding a preventative tool to stop the spread of AIDS dealt a severe blow in September when Merck's experimental HIV prevention vaccine, known as V520, failed to show protection against global pandemic, HIV/AIDS.

After determining that the AIDS vaccine does not stop HIV infections, the AIDS researchers immediately halted the international Merck vaccine trials that took place in the United States and other countries.

The trials were conducted in 15 cities in the United States, including Boston, Los Angeles and New York, and three in Canada, along with Peru, Brazil, Australia, Haiti, the Dominican Republic and Jamaica. Began in December 2004, those trials included 3,000 participants, mostly gay men.

In the American trial, which was an international phase II 'test of concept' trial in uninfected volunteers at high risk for acquiring HIV infection, the researchers included the volunteers most of whom were either homosexual men or female sex workers. They all were free of HIV at the beginning of the study, but were at high risk for getting the dreaded virus.

According to Glenda Gray, the lead South Africa investigator for the vaccine study, researchers there discovered last month that 19 volunteers out of 672 who were given two doses of the actual vaccine became infected with HIV, while only 11 of 691 who were given the placebo became HIV positive.

Researchers have now begun contacting the volunteers of the trial, mostly through text messaging, to tell each one individually whether he or she had received a placebo or the vaccine.

The Merck vaccine’s failure is not only a big disappointment for the developer, it even has shattered hopes of all the AIDS preventing agencies and AIDS researchers who were desperately waiting for a preventative vaccine to treat the lethal infectious disease.

HIV AIDS is spreading like forest fire worldwide AIDS, affecting nearly 40 million people globally. The infectious disease is now transmitted mostly during sex between a man and a woman.

Sub-Saharan Africa is the worst hit region by the HIV virus, accounting for almost two-thirds of all HIV infections and 72 percent of global AIDS deaths, the UN AIDS agency leading the battle against the disease reported in November 2006. The epidemic has engulfed more than 25 million sub-Saharan Africans since the incurable disease was first emerged in 1981. A huge and disproportionate 59 percent of sub-Saharans Africans with HIV are women, the report added.

China, the world’s most populous nation, is another AIDS-hit region. In 1998, China's Ministry of Health had estimated that 10 million citizens of China could be living with HIV infection by 2010 unless a vigorous program of prevention and treatment of the dreaded virus was launched.

According to the new 2006 estimates released recently by the National AIDS Control Organization (NACO), supported by UNAIDS and WHO, national adult HIV prevalence in India is approximately 0.36%, which corresponds to an estimated 2 million to 3.1 million people living with HIV in the country.