Science knows more than ever about how to use HIV treatment to prevent new infections but will it be enough to end Aids?
The HIV world today looks completely different than in 2004 when the South African government introduced free HIV treatment. The drugs are easier to take, have fewer side-effects and can also be used to prevent people from getting infected with HIV. Here’s what we’ve got and how we can use antiretrovirals (ARVs) to help end Aids by 2030.
The three-in-one pill
The most commonly chosen regimen for treatment is an all-in-one-pill, or fixed dose combination, that contains the antiretroviral drugs tenofovir, emtricitabine and efavirenz. These pills suppress HIV in an infected person’s body so well that they allow for the immune system to be restored. As a result, people with HIV fall sick less often and live for longer.
This three-in-one pill has predictable side effects that are usually minor. Because people only have to take one instead of three pills, they are also more likely to adhere to the treatment. The ARVs contained in the three-in-one pill also have few side effects – this also helps people to adhere to their treatment.
The new ARV ‘kid’ on the block
The latest ARV to watch is a drug called dolutegravir. It fits into a novel class of medications known as integrase inhibitors. They prevent HIV from integrating its genetic material into human cells, thus stopping HIV in its tracks. Dolutegravir may offer considerable advantages over current best-treatment. A 2016 study in The Lancethas shown dolutegravir to be even better than efavirenz, one of the ARVs in the three-in-one pill, at suppressing HIV. It also causes fewer side effects, is easy to take and should cost the same, or potentially even less, than other available ARVs. It is likely that the health department will incorporate dolutegravir into its treatment programme.
Test and treat
Until recently, people with HIV only started treatment when HIV had caused detectable immune system damage. This was measured by a CD4 count, which is an indication of how weak or strong someone’s immune system is – the lower the count, the less well the immune system functions.
But two recent research studies, the Start and the Temprano trials, both of which were published in 2015 in theNew England Journal of Medicine, have shown the best way to treat HIV infection is for someone to start on ARVs as soon as possible after being diagnosed, regardless of the person’s CD4 count. Early treatment keeps positive people much healthier. In September, South Africa’s health department started to offer everyone who tests HIV positive immediate, free access to ARVs.
ARVs can halt the transmission of HIV
It has now been proven that, because ARVs decrease the amount of virus in HIV-positive people’s bodies, they make people far less likely to transmit the virus. In fact, 96% less likely, according to the HPTN 052 study, which was published in the New England Journal of Medicine this year. This is known as treatment as prevention, or Tasp, and is a massive step forward.
Previously, HIV prevention centred on preventing body fluids from being transferred during sex with the use of condoms or choosing not to have penetrative sex. Tasp has added one more very effective option to the prevention menu.
An HIV prevention pill
Pre-exposure prophylaxis, or PrEP, in the form of an HIV prevention pill, is one of the most exciting developments in the HIV prevention world. It has the potential to be an extremely powerful tool in turning the tide on the epidemic – if it’s taken daily, it can reduce someone’s chances of getting infected with HIV between 44% and more than 90%, depending on how well it’s taken, studies have shown.
The HIV prevention tablet is a two-in-one pill: it consists of two ARVs, tenofovir and emtricitabine, which is taken daily by people who are HIV negative, but likely to be exposed to HIV. For example, PrEP could be used by an HIV-negative woman whose husband is HIV positive, but not yet on treatment. PrEP is of great benefit to groups in society who are at particularly high risk of contracting HIV: discordant couples, where one person is HIV positive and the other negative, sex workers, men who have sex with men and young women.
In June, the health department started to provide PrEP for free to 10 sex worker programmes. PrEP is also available for men who have sex with men at two state-sector clinics operated by the health department in partnership with the Anova Health Institute’s Health4Men initiative. PrEP is also available in the private sector – a GP can prescribe it.
PrEP might have some drawbacks aside from the need for daily pill taking. A small number of people, about one in 10, develop gastric side effects, such as nausea or bloating, which usually self-resolves within a few weeks. In rare cases, PrEP can affect organs such as the kidneys. A few blood tests are therefore required to ensure that PrEP is being well tolerated by the body and is not causing any unexpected toxicity.
PrEP does not protect against any other sexually transmitted infection besides HIV. People who use PrEP in lieu of condoms might therefore be at risk of sexually transmitted infections, even though their risk of HIV is massively reduced. It is best to use PrEP together with condoms for maximum sexual protection.
An HIV emergency pill – but you have to take it for a month
Postexposure prophylaxis, or PEP, is not new. This is when HIV-negative people take ARVs after they think they’ve been exposed to HIV, for instance after a condom has broken or following a rape incident. PEP has been around for at least a decade, but knowledge and use of it remains unfortunately low.
PEP consists of a one-month course of three types of ARVs that can reduce the risk of HIV infection by about 80%, according to a 2016 study in the journal Clinical Infectious Diseases. It has to be taken within 72 hours after exposure to HIV – the sooner it’s taken the more effective it is. It is available for free at state clinics to rape survivors and other people who have had a potentially high-risk exposure to HIV.
PEP is sometimes difficult to access as it is often required after the usual operating hours of daytime clinics or GP practices. This, together with a lack of knowledge among both potential PEP users and providers, creates a structural barrier to accessing PEP. The fact that PEP is sought after HIV exposure, in an emergency situation, is also a hindrance as anxiety and distress may affect people’s motivation to seek PEP.
Dr Kevin Rebe is an infectious diseases physician working for the Anova Health Institute’s Health4men project in Cape Town.