College and primary school students hold a giant red ribbon made by themselves during an event to raise awareness of HIV/AIDS on the World AIDS Day, in Fuyang, Anhui province December 1, 2014. (REUTERS/Stringer)

Ever since anti-retrovirals became the standard therapy for HIV in the late 1980s, physicians have agonized over the timing of when to give the drugs.

While the treatment has proven effective at decreasing patients' viral load, it often comes with severe, even toxic side effects -- a worry that led global public health officials to recommend only giving the drug when a patient's white blood cell levels drop to a certain level.

Now it looks like the guidelines may have been too conservative.

The results of a National Institutes of Health study revealed on Wednesday, involving 4,685 patients in 35 countries, show that the treatment appears most effective when you start it at the time of diagnosis. The trial, nicknamed START (Strategic Timing of AntiRetroviral Treatment), began in 2011 and was supposed to run until 2016 but was ended early when an interim review of the data showed a large difference between those who received treatment early and those who received treatment when their CD4+ cell count declined to under 350 cells/mm3.

[Southern states are now epicenter of HIV/AIDS in the U.S.]

The researchers were surprised to find that the risk of developing serious illness or death was reduced by more than half -- 53 percent -- in the early treatment group. The results were so striking that the researchers felt ethically obligated to offer the antiretroviral drugs to all the patients in the trial, effectively ending their scientific inquiry.

Following the announcement of the results, the United Nations AIDS agency called for everyone with HIV to get immediate access to antiretroviral therapy.

“Delaying access to HIV treatment under any pretext is denying the right to health,” said Michel Sidibé, executive director of UNAIDS.

The findings are likely to dramatically change the approach for treating HIV-positive individuals around the globe. U.S. treatment guidelines already recommend that all HIV-infected patients take antiretrovirals whatever their CD4+ count may be. But those standards were in conflict with World Health Organization guidelines that recommend that individuals begin therapy when their CD4+ counts fall to 500 cells/mm3 or below. Many countries have adopted policies that are in line with the WHO recommendations.

“We now have clear-cut proof that it is of significantly greater health benefit to an HIV-infected person to start antiretroviral therapy sooner rather than later," said Anthony S. Fauci, director of the National Institutes for Allergy and Infectious Diseases.