New HIV cases increased in 2023

The overall trend is still firmly downwards, but the number of late diagnoses is a worry.

---

HIV case numbers have declined over the last decade, but the proportion of cases diagnosed late has increased over the same period.

The number of HIV cases reported across the nation in 2023 increased compared to 2022, but the long-term trend of declining diagnoses is promising, according to data released this week by the Kirby Institute.

Last year there were 722 new diagnoses of HIV, an increase from the 553 seen in 2022. However, this is a blip amid the steady decline over the last decade – a 33% reduction in total case numbers from the 1079 reported in 2014.

“These long-term reductions tell us our strategies to eliminate HIV transmission – such as testing, HIV pre-exposure prophylaxis (PrEP) and treatment – are working,” said Kirby Institute surveillance innovation group lead Dr Skye McGregor.

“With effective treatment, levels of HIV in the blood are so low they are undetectable, meaning HIV can’t be transmitted to sexual partners. In other words, undetectable = untransmittable, or U=U. However, we also need to look carefully at the inequities revealed by the data and intensify our efforts to respond to HIV.”

There has been a particularly significant reduction in the number of new HIV diagnoses among Australian-born gay and bisexual men, where case numbers have fallen by 64% over the last decade.

However, there has been a small increase in the number of HIV diagnoses in people who engage in heterosexual sex. There were 200 cases recorded in 2014, a peak of 237 cases in 2017, and 205 cases in 2023.

“While these are only small increases, when viewed against a backdrop of declines overall, this highlights where we need to focus additional efforts over the next decade,” Dr McGregor said.

Testing numbers for HIV bounced back in 2023 following “considerable declines” during the covid pandemic, but Dr McGregor feels there is a greater need for earlier testing across Australia.

In 2023 37% of new HIV cases were classified as a “late” diagnosis, meaning the individual could have been living with HIV for years without knowing – potentially experiencing HIV-related illness and unknowingly spreading the virus.

Over half of heterosexual individuals diagnosed with HIV last year were diagnosed with late-stage HIV.

“The number of late diagnoses is very concerning. We need to increase access to testing, treatment and prevention in a targeted and equitable way, to ensure those most in need can easily access services,” Dr MacGregor said.

“Regular sexual-health testing is important for anyone who has changed sexual partners or who hasn’t used a condom. A blood test for syphilis and HIV should be part of your routine sexual health screen with your GP.”

In other HIV-related news, a recent retrospective study of almost 6000 individuals with HIV who initiated antiretroviral therapy within 12 months of diagnosis has identified a direct link between ART and weight gain.

The findings, published in The Lancet HIV, report that weight gain varied with the type of treatment administered and that weight increases were seen regardless of what BMI category the patient belonged to at baseline.

Individuals who had a BMI < 30 prior to starting an integrase strand transfer inhibitor or tenofovir alafenamide-based regimen gained an average of 4.8kg over a three-year period.

The largest increases in weight were seen in women with a BMI of 18.5-24.9 who were placed on an integrase strand transfer inhibitor-based regime (average weight gain of 5.6kg over the three-year follow-up).

“Given the known risk for cardiometabolic disease, bodyweight management needs to be part of the overall care of individuals prescribed these drugs,” the researchers concluded.

The Lancet HIV, 23 August 2024