New hope to halt spread of HIV

published on July 19, 2010 in Toronto Star

A new study by a Canadian researcher that shows a substantial drop in HIV transmission has triggered a dramatic shift in UNAIDS treatment strategy.

A British Columbia study has found a 52 per cent reduction in the number of HIV cases in that province from 1996 to 2009, according to a report published in Lancet.

The study also found a similar drop in a smaller population base of intravenous drug users.

The study, published in Lancet on Sunday, the same day the 2010 AIDS Conference kicked off in Vienna, proves as far as its authors are concerned that the treatment of HIV/AIDS with a cocktail of drugs not only benefits individual patients but also lowers the transmission of new cases of the disease.

Until a vaccine or cure is found – something that is many years away despite new breakthroughs, including the recent discovery of two antibodies that neutralize most strains of AIDS in the laboratory – the best way to stop the pandemic in its tracks may be a worldwide rollout of a cocktail of highly active antiretroviral drugs for patients that qualify for them, according to Dr. Julio Montaner, president of the International AIDS Society and a Vancouver researcher.

Montaner, the chair in AIDS Research at University of British Columbia’s Faculty of Medicine, and his team at the B.C. Centre of Excellence in HIV/AIDS found that between 1996 and 2009 the number of patients receiving the Highly Active Antiretroviral Therapy, or HAART, rose from 837 to 5,413. At the same time the number of new HIV diagnoses fell from 702 to 338 a year.

The dramatic drop led him to call for a change in treatment philosophy.

“Our results provide a strong rationale for re-examination of the HIV prevention and treatment dichotomy, as has been strongly advocated by the UN Joint Programme on HIV/AIDS as part of a comprehensive combination prevention strategy,” writes Montaner in Lancet.

“Furthermore, our results should serve to re-energize the G8’s universal access pledge as a means to curb the effect of AIDS and the growth of the HIV pandemic.”

Montaner’s study has triggered a shift in UNAIDS treatment strategy. On the eve of the AIDS conference, the UN agency announced Treatment 2.0, based on the results of Montaner’s study and other supporting evidence.

“He has been an important partner in developing the strategy and the concepts the way they stand now,” explained Dr. Bernhard Schwartlander, director for evidence strategy and results with UNAIDS. “We estimate that probably one-third of all infections could be avoided simply by treating all of those who should be treated.”

That means up to 1 million new HIV infections could be avoided. “We have to move away from seeing a treatment program as a cost factor to recognizing it as a . . . smart investment, because not only will we keep people healthy, alive and productive, we will also avoid new infections.”

Montaner was one of the first to recognize that treatment may have an effect on prevention, he said. His work “was certainly one of the elements that led to us putting these pieces together,” acknowledged Schwartlander.

UNAIDS estimates there were 33.4 million people living with HIV worldwide at the end of 2008. In the same year there were 2.7 million new HIV infections.

The new AIDS treatment program calls for a massive rollout of antiretroviral treatment for those who qualify, the acceptance of treatment as a form of prevention, the simplification of the medical treatment and monitoring, the creation of even cheaper and less toxic drugs, and an increase of voluntary HIV testing and counselling.

Steps must also be taken to streamline the medical expenses associated with HIV in the developing world, which would result in more money being directed toward the rollout of drugs to more patients.

“We have to simplify medical treatment to the primary-care level, where people can be reached at their houses, in their villages,” Schwartlander said.

Models suggest that implementing this new strategy could result in averting an additional 10 million deaths by 2025, according to UNAIDS.

So what accounted for the rapid decrease in new HIV cases in the B.C. study?

According to Montaner it’s simple: As patients in B.C. received HAART treatment and as the level of free and easily accessible treatment expanded across the province, the level of the AIDS virus in patient’s blood, semen and vaginal secretions became virtually undetectable.

That meant the risk of transmitting the disease was close to nil, and therefore the level of transmission and new cases dropped substantially.

“All of the above occurred as a result of us being able to drastically reduce the amount of viral load in the community,” Montaner said in an interview with the Star before he left for Vienna.

That’s despite an ever-growing rate in other sexually transmitted diseases in B.C., such as gonorrhea, syphilis and Chlamydia, according to Montaner.

“We have shown a strong population-level association between increasing HAART coverage, decreased viral load, and decreased the number of HIV diagnoses per year,” Montaner and his coauthors wrote in the study.

“Our results support the proposed secondary benefit of HAART used within existing medical guidelines to reduce HIV transmissions.”

Montaner and his fellow researchers used two separate databases to do their work: the British Columbia Centre for Disease Control, a provincial agency that centralizes all HIV surveillance data; and data for viral loads and CD4 cell counts and HAART use from the British Columbia Centre for Excellence in HIV/AIDS.

The team looked at three distinct periods based on antiretroviral use in B.C. The first was 1996 to 1999 during the first rollout of HAART treatment; 2000 to 2003 and 2004 to 2009.

The study found that between 1996 and 1999, there was a steep increase in HAART use. During this period the number of HIV new cases declined 40 per cent.

From 2000 to 2003, the HAART use increased only slightly and the number of HIV diagnosis remained stable.

Between 2004 and 2009, the new HIV cases per year decreased by 23 per cent.

When data was stratified by the history of intravenous drug use, there was also a decrease of about 50 per cent, from 159 new HIV cases in 1999 to 80 cases in 2009.

A study Montaner did in 2006 also showed a decreased in potential AIDS cases. He created a hypothetical population-based model, which showed that over a 45-year period, transmission of HIV could be cut substantially with proper antiretroviral treatment of patients.

At the Toronto AIDS Conference in 2006, Montaner suggested that a widespread rollout of the use of a cocktail of drugs could reduce transmission rates. “We must stress that we do not see HAART as a replacement for the prevention effort—including vaccine research – but rather an essential part of it,” he said at the time.

“I came out saying if we treat aggressively more people and stop thinking of saving money and spend more, we will decrease HIV transmission and morbidity,” Montaner said last week before he left for the AIDS conference. “Treatment shuts down the virus’s ability to replicate itself, and it becomes undetectable.”

But his views in 2006 were perceived by some as “controversial,” triggering a quiet debate within the AIDS research and medical community.

“We’re still chasing our tail,” said Montaner. “We need to step up the role of treatment so it can reshape the curve so the epidemic can contract rather than constantly expand.”

Neither Montaner nor Schwartlander suggest that regular prevention methods be abandoned.

“We are not advocating everyone with HIV get treatment so there wouldn’t be transmission,” said Schwartlander. “What we’re saying is if you treat everyone who is eligible for antiretroviral therapy, we will have a significant effect on prevention. But it won’t entirely stop the epidemic. Other prevention tools are still important.”

The 2010 AIDS Conference in Vienna is also calling on world leaders to re-examine policies on the war on drugs. Outside of sub-Saharan Africa injecting drug use is responsible for one in three new cases of HIV and in some countries in Eastern Europe and Asia it is the primary cause of new HIV infections.

Reprinted under license from the Toronto Star.

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