A new study finds after antiretroviral therapy, latent HIV cells only 'wake up' once a week. Previously, it was thought they awoke four to five times a week.
The study was conducted by Prof. Miles Davenport and colleagues from the Kirby Institute at the University of New South Wales (UNSW) in Australia.
Worldwide, there are around 35 million people living with HIV (human immunodeficiency virus), with the majority of these residing in Sub-Saharan Africa.
According to the World Health Organization (WHO), there has been a significant increase in the number of people with HIV receiving antiretroviral therapy (ART) in recent years, with more than 2 million individuals newly enrolled to the treatment in 2013.
There is no doubt that ART - which involves the use of three or more drugs to stop HIV cells reproducing - has proved an effective prevention and treatment strategy for HIV. WHO say the likelihood of an HIV-infected individual transmitting the virus to their partner is reduced by 96% if they are receiving the treatment.
But Prof. Davenport notes researchers in the field of HIV are working toward bigger objectives. "At the moment we have very successful drug treatments for HIV, but a broader goal is to get people off antiretroviral therapy entirely," he says.
Latent HIV cells awake 24 times less than previously thought
Previously, researchers thought that among individuals with HIV who had completed antiretroviral therapy (ART), latent HIV cells - infected cells that reproduce at low levels - awoke around four or five times daily.
In order for a patient to enter remission - where no symptoms are displayed - for an average of 1 year, researchers estimated that the number of latent HIV cells would need to be reduced by around 2,000 times.
However, the study from Prof. Davenport and colleagues reveals that HIV cells only awake once a week after ART is ceased - around 24 times less than previously thought - meaning the number of latent HIV cells needed to produce a 1-year remission period would only need to be reduced by around 50-70 times.
"Researchers have been looking at ways of reducing the amount of latent HIV infection in the body, in the hopes of creating a remission so that drug therapy can be suspended," says Prof. Davenport, "but until now we didn't know exactly how long it takes for the latent HIV cells to reactivate and start infecting other cells again after treatment is suspended."
"Our findings represent an important advance in our knowledge about how HIV works," he adds.
Findings provide 'a more accurate target for HIV remission'
To reach their findings, the team analyzed data from the Kirby Institute's PULSE study and three other studies involving patients with HIV undergoing ART therapy.
The researchers combined all the data and applied mathematical modeling and statistical analysis to estimate the average frequency of viral rebound among the patients following ART.
Across all four studies, the team found that latent HIV cells "wake up" an average of once every 5-8 days - a finding they say brings researchers closer to getting HIV patients off ART completely.
Prof. Davenport says:
"While it was previously thought the latent virus 'woke up' many times a day during treatment, we now know that that latently infected cells wake up on average only once a week when treatment has been suspended.
For the first time, we have a measurement of how much we will need to reduce the viral reservoir to produce HIV remission. Essentially, we now have a more accurate target to aim for."
Earlier this week, Medical News Today reported that WHO has validated Cuba as the first country to eliminate mother-to-child transmission of HIV and syphilis.