HIV Transmission and prevention | Body Positive News

HIV Transmission and prevention

01May17
HIV transmission has reached a new record high of 244 cases in New Zealand in 2016. This follows a consistent upward trend that has been happening since 2011. Most of the cases 159 or 65% were amongst men who have sex with men with the majority 98 or 61.6% of these infections taking place within New Zealand. Amongst the Heterosexual population there were 42 new diagnoses with 11 of these infections being local.

For people not diagnosed and infected locally they may have been living with HIV for a period of time and have been engaged in care elsewhere and have just returned to New Zealand (from Australia or the UK for example) and their diagnosis is defined as “new” to New Zealand. We will always have these types of new diagnosis as people are allowed to migrate to NZ while living with HIV – which is a good thing.

When we look at our prevention efforts we are operating at the local level to prevent local transmission and the numbers relevant to this strategy are the 98 MSM and the 11 heterosexuals mentioned earlier. These are the transmissions where we can make an impact and prevent them from happening. We can also alter behaviours so that Kiwis are safe when they travel overseas.

The tools available to us work mostly at a population level. Everyone should use a condom every time they have penetrative sex. For some people this isn’t possible due to latex allergies, alcohol, judgement issues or loss of pleasure. A new tool for HIV negative people to use is PrEP which is taking an HIV medication called Truvada daily to prevent HIV from being able to take hold and an infection to occur. It’s similar to the contraceptive pill but is solely focussed on preventing HIV. Both condoms and PrEP work at a population level to prevent possible exposure. Both of these strategies work when used correctly and consistently.

When looking at transmission of HIV there has been a lot of research recently which has shown that if someone living with HIV can lower their HIV Viral Load to a point where it is undetectable (or <200) they are no longer infectious and cannot pass HIV on to their sexual partners. By starting treatment early it has been shown that people live longer healthier lives and they can attain undetectable within 6 weeks. Once maintained as undetectable for 6 months the risk of sexual transmission of HIV is removed. The key with this strategy is that people need to get tested to know their status and then engage and remain in care to have a sustained undetectable viral load.

Pharmac is currently considering removing the CD4 threshold of 500 which limits peoples access to medications so that people can start earlier and reach this undetectable state quickly. HIV has recently become a notifiable disease in New Zealand and this means that everyone can access treatment regardless of their residency. These changes mean that we will have universal access to HIV treatment for everyone living with HV in New Zealand.

This gives us 3 tools to work with in the prevention of HIV Transmission. Condoms for each sexual encounter. If you are HIV negative and condoms aren’t your thing you can use PrEP. If you are living with HIV – get tested and know your status and engage with care so that you can access treatment and sustain an undetectable viral load. All effective strategies that work to prevent HIV transmission when used correctly and consistently.

HIV prevalence in New Zealand is low compared to international standards (77 per 100,000). We have approximately 3500 people living with HIV at the moment and of those 2278 or 65% are on funded treatment. We don’t know how many of those are undetectable but we do know that the new treatments work extremely well so the percentage should be high. For arguments sake we’ll assume roughly 2000 people are undetectable or 90% of those on treatment. That leaves us with 1500 that have a detectable viral load as they don’t know their status or they may not have started treatment as yet or they may have disengaged from care for some reason. A study from the US showed that 91% of new infections came from people that were not aware of their status or were not engaged in care… this makes sense when combined with the knowledge that when engaged in care and successfully being undetectable you are not infectious.

So we theoretically have 1500 local people that have the capacity to pass on HIV in New Zealand. Any number of strategies as listed above would reduce this risk (condoms, PrEP, sex that doesn’t pass bodily fluids). If there is a risky activity with someone living with HIV that has a detectable viral load there is a possibility that HIV may be transmitted. In 2016 this happened 109 times in New Zealand.

In 2016 the number of AIDS diagnoses increased by a staggering 155% from 9 to 23 with 16 of these diagnoses occurring within 3 months of the HIV diagnoses…. these people did not have a timely HIV test. Given that effective treatments are freely available to everyone we should not have any AIDS diagnoses.

If we work to have everyone receive a timely HIV test so they know they are living with HIV we will see individual behaviours change and these opportunities for transmission will diminish and people will have an opportunity to engage in care. We can do this by increasing testing opportunities by providing home testing kits, including HIV as a part of an annual checkup, proving routine testing of HIV in Emergency settings that require a blood draw, increasing community testing and offering testing outside standard working hours.

Once people know their status they need to be linked into care and supported to remain in care and be adherent to their medication. Their sexual contacts should be contacted and offered testing to ensure they are engaged in healthcare if needed. By supporting people to engage and remain in care we will see more people reach undetectable and the opportunity for transmission will drop again. Ideally if everyone knew their status and was successfully engaged in care there would be no opportunity for local transmission of HIV. This is known as Treatment as Prevention (TasP) and works with people living with HIV to prevent the transmission of HIV and is tied to the UN strategy to end HIV transmission known as 90-90-90 where: 90% of people living with HIV know their status; 90% of people that know they have HIV are engaged in care and are accessing treatment; and 90% of those on treatment have a sustained undetectable viral load. Data just released from the UK showed that increased testing and having people successfully on treatment has resulted in a significant drop in new infections.

Given the low prevalence of HIV in New Zealand this is an achievable target to end local transmission and ensure all People Living with HIV lead healthy lives.

Mark Fisher
Executive Director
Body Positive Inc.