Few viruses have been researched as intensively and for as long as HIV, and there have been significant advances in treatment.
As a result, many people with HIV now live long and healthy lives. While there is no cure, there are many effective treatments.
In this article, we explore what is meant by a “cure,” how it differs from a treatment, and we look at some possibilities and challenges.
There are effective treatments for HIV, but there is currently no cure. However, research is still ongoing.
Perhaps three people are thought to have been cured of HIV:
- Timothy Ray Brown, originally known as the “Berlin patient,” who received HIV-free blood test results beginning in 2007
- the “London patient,” whose remission began in 2019, 18 months after their antiretroviral therapy had finished
- the “Düsseldorf Patient,” whose remission also began in 2019, 3.5 months after their antiretroviral therapy had ended
After a decade of living with HIV, Timothy Ray Brown received a diagnosis of acute myeloid leukemia. He received chemotherapy and two stem cell transplants, which replace bone marrow cells with healthy ones from a donor.
On the date of the first transplant, in 2007, Brown stopped taking antiretroviral medication. After 3 months, doctors found no evidence of the virus in his bloodwork.
Now, after more than 10 years without taking HIV medication, there is still no evidence of HIV in his body.
A stem cell transplant is a risky procedure to treat cancer, and it is not scalable into an HIV cure. Still, the apparent success of this procedure has inspired more research.
What constitutes a cure for HIV is still a topic of research and debate.
There are two main types of cure under investigation:
- a sterilizing cure, which would eliminate the virus from a person’s body
- a functional cure, which would reduce the amount of the virus in the body to undetectable levels — without using antiretroviral medicines
The International AIDS Society have defined a sterilizing cure as “the complete eradication within an individual of all replication-competent HIV.”
This is also known as the “infectious disease model.” It means that a person has at most one copy of HIV RNA per milliliter (ml) of blood.
HIV is a retrovirus, which means that it uses RNA as its genetic material. HIV treatments are, therefore, called antiretroviral medications.
Viral RNA is in the genome of infected cells and is passed down when the body makes new cells. However, the infection can remain latent in the DNA of the cells for many years without producing infectious HIV viruses. For this reason, a sterilizing cure remains impossible.
Timothy Ray Brown is considered to have experienced this because his cells with the latent infection were killed. His new cells from bone marrow transplantation were resistant to new HIV infection within his body.
Someone with a functional cure would have low levels of the dormant virus in their body. They would not need to take medication to maintain this state and would have no risk of transmitting the virus.
This type of cure is also known as the “cancer model,” as the aim is long-term remission with fewer than 50 copies of viral RNA per ml of blood.
Some research has found that certain people who receive antiretroviral therapy very soon after they contract HIV can achieve long-term remission without medication. Doctors and researchers sometimes refer to people who receive this treatment as “post-treatment controllers.”
Recently, research has explored “elite controllers” as a possible model for an HIV cure.
Elite controllers are the roughly 1% of HIV-positive people who can maintain very low viral loads for years without taking antiretroviral medication.
Establishing how this works is a major focus of research, at present.
Currently, a main goal of HIV treatment is to reduce the viral load to an undetectable level.
The viral load is the amount of HIV in a person’s blood. Viral load tests measure the number of copies of HIV RNA in a milliliter of blood.
If a person’s viral load stays undetectable, they effectively have no risk of transmitting HIV to a sexual partner who is HIV-negative. Their chances of living a long and healthy life are similar to those of someone without HIV.
People with HIV should start taking antiretroviral treatment as soon as possible, the United States Department of Health and Human Services emphasize.
These types of medication stop the virus from replicating in the body. A person may need to take a daily dose of three or more medicines, as different antiretroviral medications interrupt the life cycle of the virus in different ways.
Treatments to prevent HIV transmission
There are also preventive HIV treatments, including:
- Postexposure prophylaxis, or PEP: A person who may have been exposed to HIV can take this medication within 72 hours to help prevent transmission.
- Pre-exposure prophylaxis, or PrEP: HIV-negative people who have a high risk of exposure to the virus can take this type of medication daily.
- Preventing transmission during pregnancy, childbirth, and breastfeeding: Certain HIV medications can protect the growing fetus, and a doctor may administer medication after birth. Having a cesarean delivery and not breastfeeding can also help prevent HIV transmission.
Researchers working on possible HIV cures face a range of challenges.
A major barrier to developing a cure for HIV is that the virus can lie dormant in reservoirs of T-cells and other cells throughout the body, sometimes for decades.
The U.S. government’s timeline of HIV and AIDS highlights the advances and setbacks on the road to possible cures, treatments, and vaccines. These include the recent development of a tool to assess possible cures by counting the cells in an HIV reservoir.
Another challenge is that HIV alters the person’s immune responses, and researchers face ethical concerns. Current HIV treatments are very effective. This means that researching a cure might involve asking trial participants to expose themselves to additional risks, such as by stopping their medication.
A technological barrier involves the ability to detect the virus at low enough levels to know whether it has truly been eliminated.
The history of HIV highlights the unpredictability of medical research, despite a large global effort over several decades. It also shows many promising advances.