23rd European Meeting on HIV & Hepatitis 2025
5 key take home messages
We are pleased to share a selection of key scientific highlights from the meeting. Curated by Prof. Francesca Ceccherini-Silberstein, these take-home messages reflect some of the most relevant findings and discussions that emerged during the sessions.
APOBEC Wins Again
This year again, the role of APOBEC associated mutations in HIV drug resistance and the challenges in their interpretation using next generation sequencing were widely discussed on several occasions.
These hypermutations and APOBEC related stop codons are typically associated with defective proviral genomes, and their accurate consideration is essential for interpreting proviral DNA resistance testing. Their prevalence and potential to confound resistance profiling highlight the importance of comprehensive mutation analysis, including the consideration of cutoff thresholds, quality scores, and co-occurring mutations.
Refining NGS based resistance reports by accounting for these factors can improve the accuracy of HIV drug resistance interpretation and help optimize treatment decisions.
By using near full length amplification of the HIV-1 genome in combination with long read sequencing, it becomes possible to distinguish APOBEC associated mutations from potentially replication competent populations in proviral DNA. Characterizing the proviral population in terms of replication competence may prove helpful in ART switch settings with limited treatment options.
Comparable Dynamics of Cell-Associated HIV-RNA, Total and Intact Proviral HIV-1 DNA in Virologically Suppressed People with HIV Switching to 2DR or Continuing 3DR Over an 18-Month Follow-up
Two-drug antiretroviral therapy (2DR-ART) regimens are increasingly being used, offering comparable efficacy and reduced drug toxicity compared to 3DR-ART. However, little is known about the differential impact of 2DR-ART versus 3DR-ART regimens on the HIV blood reservoir.
Fiaschi et al. from the University of Siena presented an observational prospective pilot study investigating whether switching virologically suppressed people with HIV from 3DR-ART to 2DR-ART affects their HIV reservoir. Cell-associated HIV-RNA and HIV-DNA were found to correlate with each other, but not with intact HIV proviruses in CD4+ T cells at baseline (T0).
All three parameters showed comparable dynamics over 18 months, irrespective of treatment, providing reassurance that switching to 2DR does not affect the size of the viral reservoir in the medium term. Prolonged follow-up and additional studies are needed to establish the clinical utility of these new molecular markers of the HIV reservoir before treatment simplification. This presentation received the Ricardo Camacho Award 2025.
We Must Open All the Doors to Expand the Potential Use of New Antivirals — But Let’s Remember the Risk of Resistance
Long-acting antivirals represent important options and strategies for both treatment and prevention. Lenacapavir, the first capsid inhibitor administered via subcutaneous injection every six months, introduces a novel multimodal mechanism of action. Its attributes, demonstrated in clinical trials—for treating people with multidrug-resistant HIV as part of combination therapy and for prevention as a single agent—mark a turning point in the history of HIV care.
There is growing excitement around ongoing studies investigating once-weekly oral and twice-yearly injectable treatments with long-acting antiviral regimens. However, the wider use of these drugs (currently the combination of cabotegravir and rilpivirine, or lenacapavir) and their relatively modest genetic barrier raise valid concerns about the risk of resistance in the event of treatment failure.
Notably, the emergence of resistance is already significant in low- and middle-income countries with dolutegravir, a drug considered to have a high resistance barrier. Therefore, careful monitoring and further research are essential to minimize the risk of increasing resistance in global HIV treatment strategies.
Don't Forget HBV in Treating HIV
A low but significant risk of HBV reactivation in people with HIV and evidence of prior HBV infection are important factors to consider when weighing the risks and benefits of discontinuing HBV active ART in favor of other treatment regimens.
HBV reactivations can occur across a wide range of CD4 counts and HIV RNA levels, although the risk is generally higher in cases of HIV viraemia, low CD4 counts, nadir CD4 counts below 100 cells per cubic millimeter, and detectable HBV DNA prior to switching. T
he presence of anti-HBs reduces but does not eliminate the risk. A thorough assessment of both HIV and non-HIV related reactivation risk factors is essential before switching and should continue after the switch, accompanied by a predefined monitoring plan. The standardization of HBV monitoring practices before and after switching remains a critical need.
An Open Window to the Hidden HDV
Chronic HDV infection causes more severe liver disease than chronic HBV monoinfection, accelerating liver fibrosis, increasing the risk of hepatocellular carcinoma, and leading to earlier hepatic decompensation than in patients infected with HBV alone. However, uncertainties about the true prevalence of HDV infection and several gaps in HDV screening still persist across Europe.
In the hepatitis session, a local Delta double reflex strategy study from Spain was presented, along with a large European study investigating HDV screening rates and factors associated with the lack of HDV screening among HBsAg positive individuals. Data from more than 15,000 HBsAg positive people attending 16 tertiary European centers between 2021 and 2023 were collected. The rate of HDV screening varied widely across regions. In particular, screening was lower in Eastern Europe (23.9 percent), where the highest rate of anti-HDV positivity (9.9 percent) was observed.
Compared to individuals with HBV infection, anti-HDV positive people had significantly higher HBsAg levels, lower HBV DNA, and more advanced liver disease. HIV coinfection was also more common (10.8 percent versus 4.1 percent, p < 0.001). Notably, the study observed a small but appreciable proportion of people (2 percent) with detectable HDV RNA despite a lack of anti-HDV antibodies, underscoring the need for greater standardization of HDV diagnostics. Overall, there is an urgent need to improve and harmonize HDV diagnostic measures and promote access to antiviral treatment at the European level.
Highlights from the 23rd edition
Save the Date
The next edition of this meeting will return to Barcelona, Spain in 2026. We look forward to welcoming you again for another eventful program.