HIV Progress Report: Are We Close to a Cure?

The development of a vaccine for HIV would save millions of lives. However, researchers haven’t yet discovered an effective vaccine for HIV. In 2009, a study published in the Journal of Virology found that an experimental vaccine prevented about 31 percent of new cases. Further research was stopped due to dangerous risks. In early 2013, the National Institute of Allergy and Infectious Diseases stopped a clinical trial that was testing injections of the HVTN 505 vaccine. Data from the trial indicated the vaccine didn’t prevent HIV transmission or reduce the amount of HIV in the blood. Research into vaccines is ongoing throughout the world. Every year there are new discoveries. In 2019, researchers at the University of Pittsburgh announced they’d developed a promising treatment allowing them to:

1. engineer certain immune system cells to reactivate HIV in cells that contain inactive, or latent, HIV
2. use another set of engineered immune system cells to attack and remove cells with reactivated HIV

Their findings could provide the foundation for an HIV vaccine. Clinical trials are in the works.

Although there’s no HIV vaccine yet, there are other ways to protect against transmission. HIV is transmitted through the exchange of bodily fluids. This can happen in a variety of ways, including:

• Sexual contact. During sexual contact, HIV can be transmitted through the exchange of certain fluids. They include blood, semen, or anal and vaginal secretions. Having other sexually transmitted infections (STIs) can increase the risk of HIV transmission during sex.
• Shared needles and syringes. Needles and syringes that have been used by a person with HIV may contain the virus, even if there’s no visible blood on them.
• Pregnancy, delivery, and breastfeeding. Mothers with HIV can transmit the virus to their baby before and after birth. In instances where HIV medication is used, this is extremely rare.

Taking certain precautions may protect a person from contracting HIV:

• Get tested for HIV. Ask sexual partners about their status before having sex.
• Get tested and treated for STIs. Ask sexual partners to do the same.
• When engaging in oral, vaginal, and anal sex, use a barrier method like condoms every time (and use it correctly).
• If injecting drugs, make sure to use a new, sterilized needle that hasn’t been used by anyone else.

Pre-exposure prophylaxis (PrEP) is a daily medication used by people without HIV to lower their chances of contracting HIV, if exposed. It’s highly effective in preventing the transmission of HIV in those with known risk factors. Populations at risk include:

• men who have sex with men, if they’ve had anal sex without using a condom or have had an STI in the last six months
• men or women who don’t use a barrier method like condoms regularly and have partners with an increased risk for HIV or an unknown HIV status
• anyone who has shared needles or used injected drugs in the last six months
• women who are considering conceiving with HIV-positive partners

According to the Centers for Disease Control and Prevention (CDC), PrEP can reduce the risk of contracting HIV from sex by around 99 percent in people with known risk factors for HIV. For PrEP to be effective, it must be taken daily and consistently. Everyone at risk for HIV should begin a PrEP regimen, according to a recent recommendation from the US Preventive Services Task Force.

Post-exposure prophylaxis (PEP) is a combination of emergency antiretroviral drugs. It’s used after someone may have been exposed to HIV. Healthcare providers may recommend PEP in the following situations:

• A person thinks they may have been exposed to HIV during sex (e.g., the condom broke or no condom was used).
• A person has shared needles when injecting drugs.
• A person has been sexually assaulted.

PEP should only be used as an emergency prevention method. It must be started within 72 hours of possible exposure to HIV. Ideally, PEP is started as close to the time of exposure as possible. PEP typically involves a month of adherence to antiretroviral therapy.

Diagnosing HIV and AIDS is a vital step toward preventing HIV transmission. According to UNAIDS, a division of the United Nations (UN), around 25 percent of HIV-positive people worldwide don’t know their HIV status. There are several different blood tests that healthcare providers can use to screen for HIV. HIV self-tests allow people to test their saliva or blood in a private setting and receive a result within 20 minutes or less.

Thanks to advances in science, HIV is considered a manageable chronic disease. Antiretroviral treatment allows people living with HIV to maintain their health. It also reduces their risk for transmitting the virus to others. Around 59 percent of all people with HIV receive some type of treatment, according to UNAIDS. The medications used to treat HIV do two things:

• Reduce viral load. The viral load is a measure of the amount of HIV RNA in the blood. The goal of HIV antiretroviral therapy is to reduce the virus to an undetectable level.
• Allow the body to restore its CD4 cell count to normal. CD4 cells are responsible for protecting the body against pathogens that can cause HIV.

There are several types of HIV drugs:

• Non-nucleoside reverse transcriptase inhibitors (NNRTIs) disable a protein that HIV uses to make copies of its genetic material in the cells.
• Nucleoside reverse transcriptase inhibitors (NRTIs) give HIV faulty building blocks so it can’t make copies of its genetic material in the cells.
• Protease inhibitors disable an enzyme that HIV needs to make functional copies of itself.
• Entry or fusion inhibitors prevent HIV from entering the CD4 cells.
• Integrase inhibitors prevent integrase activity. Without this enzyme, HIV can’t insert itself into the CD4 cell’s DNA.

HIV drugs are often taken in specific combinations to prevent the development of drug resistance. HIV drugs must be taken consistently to be effective. An HIV-positive person should talk with their healthcare provider before considering switching medications to reduce side effects or because of treatment failure.

Research has shown that achieving and maintaining an undetectable viral load through antiretroviral therapy effectively eliminates the risk of transmitting HIV to a sexual partner. Major studies have found no instances of HIV transmission from a persistently virally suppressed (undetectable viral load) HIV-positive partner to an HIV-negative partner. These studies followed thousands of mixed-status couples over several years. There were thousands of instances of sex without condoms. With awareness that U=U (“undetectable = untransmittable”) comes greater emphasis on “treatment as prevention (TasP).” UNAIDS has a “90-90-90” goal to end the AIDS epidemic. By 2020, this plan aims for:

• 90 percent of all people living with HIV to know their status
• 90 percent of all people diagnosed with HIV to be on antiretroviral medication
• 90 percent of all people receiving antiretroviral therapy to be virally suppressed

Researchers are hard at work looking for new drugs and treatments for HIV. They’re aiming to find therapies that extend and improve the quality of life for people with this condition. In addition, they hope to develop a vaccine and discover a cure for HIV. Here’s a brief look at several important avenues of research.

Monthly injections

A monthly HIV injection is scheduled to become available in early 2020. It combines two drugs: the integrase inhibitor cabotegravir and the NNRTI rilpivirine (Edurant). Clinical studies found that the monthly injection was as effective at suppressing HIV as the typical daily regimen of three oral medications.

Targeting HIV reservoirs

Part of what makes discovering a cure for HIV difficult is that the immune system has trouble targeting reservoirs of cells with HIV. The immune system usually can’t recognize cells with HIV or eliminate the cells that are actively reproducing the virus. Antiretroviral therapy doesn’t eliminate HIV reservoirs. Researchers are exploring two different types of HIV cures, both of which would potentially destroy HIV reservoirs:

• Functional cure. This type of cure would control replication of HIV in the absence of antiretroviral therapy.
• Sterilizing cure. This type of cure would completely eliminate the virus that’s capable of replicating.

Breaking apart the HIV virus

Researchers at the University of Illinois at Urbana-Champaign have been using computer simulations to study the HIV capsid. The capsid is the container for the virus’s genetic material. It protects the virus from being destroyed by the immune system. Understanding the makeup of the capsid and how it interacts with its environment may help researchers find a way to break it open. Breaking the capsid could release HIV’s genetic material into the body where it can be destroyed by the immune system. It’s a promising frontier in HIV treatment and cure.

‘Functionally cured’

Timothy Ray Brown, an American once living in Berlin, received an HIV diagnosis in 1995 and a leukemia diagnosis in 2006. He’s one of two people sometimes referred to as “the Berlin patient.” In 2007, Brown received a stem cell transplant to treat the leukemia — and stopped antiretroviral therapy. HIV hasn’t been detected in him since that procedure was performed. Studies of multiple parts of his body at the University of California, San Francisco have shown him to be free of HIV. He’s considered “effectively cured,” according to a study published in PLOS Pathogens. He’s the first person to be cured of HIV. In March 2019, research was made public on two other men who had received diagnoses with both HIV and cancer. Like Brown, both men received stem cell transplants to treat their cancer. Both men also stopped antiretroviral therapy after receiving their transplants. At the time the research was presented, “the London patient” had been able to remain in HIV remission for 18 months and counting. “The Dusseldorf patient” had been able to remain in HIV remission for three and a half months and counting.

Researchers barely understood HIV 30 years ago, let alone how to treat or cure it. Over the decades, advances in technology and medical capabilities have brought more advanced HIV treatments. Successful antiretroviral treatments can now halt HIV’s progression and decrease a person’s viral load to undetectable levels. Having an undetectable viral load not only improves the health of a person with HIV, but it also eliminates the risk of them transmitting HIV to a sexual partner. Targeted drug therapy can also prevent pregnant people with HIV from transmitting the virus to their children. Each year, hundreds of clinical trials aim to find even better treatments for HIV in the hopes of one day finding a cure. With those new treatments come better methods of preventing the transmission of HIV. Read this article in Spanish.