IAS 2023: Rapporteur summary track C – prevention

Simon Collins, HIV i-Base

The following report is based on an edited transcription of the rapporteur summary at the end of the conference, with additional original content added for some of the selected studies.

This issue of HTB includes summaries from Tracks A and C as Track B was included in the previous issue.

The rapporteur summary for Track C was given by Nyaradzo Mavis Mgodi from the University of Zimbabwe, provided an overview of the programme rather than selecting the most important and significant studies, included more than 30 talks and presentations. [1]

  • Towards HIV elimination.
  • Long-acting PrEP: HIV testing and estimating HIV incidence.
  • Preventing HIV and related co-infections.
  • Sexual reproductive health and STIs.
  • Human-centred approaches.

Towards HIV elimination

Many presentations related to global health goals to effectively reduce HIV transmissions and prevent HIV-related deaths by 2030, with some countries reporting optimistic results and others highlighting significant problems.

The oral abstract session ‘Progress towards HIV elimination, are we there yet?’ focussed on indicators and metrics for ending HIV transmission. [2]

This session included optimistic progress towards 95:95:95 targets in Australia (currently 92:92:98) and from the increased use of rapid/same-day ART in Thailand. [3, 4]

Difficult challenges were reported in two studies from South Africa: the increased incidence of HIV in people who use drugs (reduced by access to harm reduction packs and earlier ART) and a 200% increased risk of mortality from unplanned treatment interruptions (see Table 1 below). [5, 6].

Table 1. Increased risk of mortality linked to unplanned treatment interruption (Moolla et al) [5]

Adjusted hazard ratio (95%Cl)
Interruption status No interruption 1 (reference)
Early interrupters 2.32 (2.06 to 2.61)
Late interrupters 1.90 (1.68 to 2.15)

An oral late-breaker included results from a systematic review and meta-analysis showing the benefits of using social networks to increase the uptake of HIV testing to reach the first 95 target. [7]

Plenary session PL05 focussed on elimination of HIV in two talks. [8]

Andrew Grulich focussed on how prevention programmes measure elimination, and on progress at a global, regional and country level, with detailed results from Australia. East and Southern Africa are on track to meet elimination targets (57% reduction), but other regions lag or are seeing substantial increases on new cases. Although Australia is a low-incidence country, the 88% reduction reported in inner Sydney compares to only 31% reductions in outer suburbs where access to prevention follows different patterns. [9]

Natalia Laufer looked at the implications of U=U on HIV prevention in the context of pregnancy and breast/chest feeding. This included questions about the duration and need for neonatal PEP if ART is started before conception. This is because recent French data now report this risk of transmission as zero. So far, only the Swiss guidelines say that neonatal PEP in not needed in the context of optimal ART. Will guidelines always remain regional rather than universal? The low risks of transmission from breast/chest feeding are still based on two cases from each of the PROMISE and KIULARCO studies (all linked with low adherence, which is notably difficult post-partum). What happens with INSTI-based ART (where drug concentrations in milk are lower)? Is the earlier concern about mixed feeding still relevant? What happens in the context of mastitis? What is the role of cell-associated HIV DNA? [10]

The benefits of a community-based primary healthcare at scale, showed that Brazil’s family health strategy (FHS) has a substantial impact on reducing the incidence of advanced HIV and mortality, using data from a linked longitudinal cohort of >3.4 million people (see Table 2). [11]

Table 2. Incidence and mortality rates using Family Health Strategy, Brazil, 2007-15

Outcome Untreated






AIDS incidence 25.57

(23.71 to 27.58)


(12.65 to 13.80)


(14.45 to 15.58)

AIDS mortality 8.28

(7.25 to 9.45)


(3.58 to 4.20)


(4.22 to 4.83)

FHS coverage AIDS incidence N=3,435,068

RR (Cl 95%)

AIDS mortality N=3,435,068

RR (Cl 95%)

<20% 1 1
100% 0.76 (0.68 to 0.84) 0.68 (0.56 to 0.82)

Long-acting PrEP: HIV testing and estimating HIV incidence

Although long-acting PrEP and treatment is highly effective, many talks referred to ongoing inequity in access and practical concerns such as caution about drug resistance. Three talks in symposium 11 looked at the challenges associated with testing in the background of long-acting PrEP using CAB-LA or the dapivirine ring. [12]

This included Urvi Parikh discussing how the fear of resistance should slow down the scale-up of long-acting interventions. [13] Also, discussions on the technical challenges of testing for HIV when using long-acting PrEP. [14, 15]

Another set of invited talks in symposium 05 looked at the technical challenges of estimated background incidence of HIV and overcoming efficacy challenges now that oral PrEP is standard of care, including a talk by Deborah Donnell on use of HIV recency tests (detuned, RITA) and counterfactual placebo. [16, 17, 18, 19]

Preventing HIV and related co-infections

An oral abstract session on colliding epidemics covered other infectious diseases and the importance of person-centred public health interventions and integrated care in people living with HIV or at risk for HIV. [20]

Joseph Puyat’s presentation showed the need for flexible and adaptable guidelines for COVID vaccinations among people who inject drugs, people who are living with HIV, and those with fast waning of vaccine effectiveness. [21] Claire Pederson described the first integration of an HIV PrEP service in sub-Saharan Africa with an assisted partner notification programme in STI clinics in Malawi. [22] Thomas Carpino also described the mpox vaccination policy in the US. [23]

Sexual reproductive health and STIs

Two talks and a Q&A in a plenary session on STI and HIV prevention included a talk about STI prevention using DoxyPEP and HIV prevention using bNAbs. [24]

Jean-Michel Molina reviewed accumulating data supporting the short-term benefits of doxycycline PEP among gay and bisexual men with strong reductions on the incidence of syphilis and chlamydia (though lower and conflicting effects on gonorrhoea). The challenges with DoxyPEP include the risk of resistance, and the impact on the microbiome makes continued research important in different populations but cautious implementation might also be possible where close monitoring can track the risks. [25]

Nyaradzo Mgodi reviewed options for HIV prevention, including using bNAbs as PrEP. This included the different timelines for developing binding, early neutralising and then broadly neutralising antibodies (in a minority of people). The potential of bNAbs for prevention, for example in the large AMP studies, is limited by evolution of modern circulating strains and the challenges of testing for bNAb sensitivity, even using PT80 as a surrogate marker for efficacy. There are now seven classes of bNAbs and use of combinations or multi-specific compounds will be essential. [26]

A useful review of future developments was also just published by Malhotra et al in PIAS. [27]

Session OAC04 included four presentations related to reproductive health in different populations, mainly focussed on the safety of PrEP in low-income settings, especially in Kenya and Thailand. [28, 29, 30, 31]

The Thai study showed a lack of interactions between TAF-based PrEP and gender affirming hormones in 20 transgender women who had not undergone orchiectomy. The new data reporting similar drug levels in PBMCs and urine with and without hormone treatment supported earlier data showing no differences in plasma levels. [32]

Human-centred approaches

The importance of human-centred approaches was included in many of the presentations that are already reported above, but also in the session of late-breaking abstracts. [33]

It also included results on preferences for PrEP formulations in women in the HPTN 082 study. This found a greater preference for injectable PrEP, although a significant minority preferred oral PrEP, with choice related to initial PrEP experience. See Table 3. [34]

Table 3: Participant preferences for PrEP formulation in HPTN 084 (n=2472)

Prefer injectable – n=1931 (78%)
Overall prefer injections and/or don’t like pills 78%
In those using injections (n=1253) 89%
In those first using oral pills (n=1219) 67%
Convenient, discreet and/or easier to adhere 11%
CAB was shown to be superior to TDF/FTC 8%
Want to avoid side effects of TDF/FTC 1%
No response 2%
Prefer oral PrEP n=536 (22%)
In those using injections (n=1253) 11%
In those first using oral pills (n=1219) 33%
Concern about injection site/other side effects 5%
Clinic visits more efficient 1%
Pregnancy 1%
Other 1%
No response 11%

Perhaps most notable in the review was the insistence throughout that prevention science should be a human-centred approach that includes the choices and perspectives of the people who are most directly affected.

Whatever the specific interventions, this research should meet the following criteria.

  • To reflect diversity, equity and inclusion.
  • Target highest prevalence regions and special populations (pregnant and breast-feeding, infants, adolescents, gender diversity, women).
  • Begin with the end in mind (access, manufacturing, licensing, delivery methods).
  • Be framed by a human rights-based approach and
  • Uphold justice and kindness to achieve the best results.


Unless stated otherwise, all references are to the Programme and Abstracts of the 12th IAS conference (IAS 2023), 23–26 July 2023, Brisbaine, Australia.

  1. Mgodi NV. Rapporteur feedback Track C. IAS 2023.
  2. IAS 2023. OAC01: Progress towards HIV elimination, are we there yet? (session) (webcast)
  3. Gray R et al. Australia’s progress towards ending HIV as a public health threat: trends in epidemiological metrics over 2004-2021. IAS 2023, oral abstract OAC0102.
  4. Teeraananchai S et al. The impact of same-day and rapid ART initiation under the Universal Health Coverage program on HIV outcomes in Thailand. IAS 2023, oral abstract OAC0105.
  5. Artenie A et al. Characterising HIV incidence among people who inject drugs engaged with harm-reduction programs in four provinces in South Africa. IAS 2023, oral abstract OAC0103.
  6. Moolla H et al. The effect of unplanned care interruptions on the mortality of adults resuming antiretroviral therapy in South Africa: a survival analysis. IAS 2023, oral abstract OAC0104.
  7. Ong J et al. Should social network testing be offered as an additional HIV testing approach? A GRADE systematic review and meta-analysis. IAS 2023, oral abstract OALBC0602.
  8. Towards Elimination. IAS 2023, plenary session PL05.
  9. Grulich A. The prospect of HIV elimination through prevention programmes. IAS 2023, plenary session PL05. (see ref 8)
  10. Laufer N. Towards Elimination: Pregnancy and breastfeeding in the U=U era. IAS 2023, plenary session PL05. (see ref 8)
  11. Pinto P et al. The effect of primary health care on AIDS: a cohort study of 3.4 million individuals in Brazil. IAS 2023, oral abstract OAC0303.
  12. HIV testing in the context of long-acting extended delivery of HIV PrEP. IAS 2023 SY11.
  13. Parikh U. HIV testing in the context of long-acting extended delivery of HIV PrEP: Long-acting PrEP and the potential for resistance. IAS 2023, SY11.
  14. Hans L. HIV testing approaches: Current and new approaches and considerations for long-acting PrEP. IAS 2023, SY11.
  15. Reed J et al. Long-acting PrEP: Programmatic considerations for HIV testing. IAS 2023, SY11.
  16. Estimating HIV incidence in the era of long-acting PrEP/ IAS 2023 SY05.
  17. Donell D. Estimating HIV incidence in the era of long-acting PrEP: Novel scientific approaches for establishing efficacy of new biologics in the era of long-acting PrEP. IAS 2023, symposium SY05.
  18. Das M. Experience with using recency assays to estimate HIV incidence in an HIV prevention trial. IAS 2023, symposium SY05.
  19. Ruzagira. Experience with using a registrational cohort to estimate HIV incidence: Lessons from PREPVAcc/ IAS 2023, symposium SY05.
  20. OAC02 – Colliding epidemics: Prevention of HIV and co-infections
  21. Puyat J.H. et al. COVID-19 vaccine effectiveness by HIV status and injection drug use history. IAS 2023, oral abstract OAC0202.
  22. Pedersen C et al. Integration of PrEP services and assisted partner notification into an STI Clinic in Lilongwe, Malawi. IAS 2023, oral abstract OAC0205.
  23. Carpino T et al. Mpox vaccination among gay, bisexual, and other men who have sex with men in the United States, September-December 2022.
  24. The latest in STI and HIV prevention. IAS 2023 PL04.
  25. Molina J-M. The latest in HIV and STI prevention: Doxycycline post-exposure prophylaxis for STIs: Time for implementation? IAS 2023, plenary session PL04.
  26. Mgodi N, bNAbs for prevention. IAS 2023, plenary session PL04.
  27. Malhotra S et al. Antibodies for HIV prevention: the path forward. J Int AIDS Soc. 2023 May;26(5):e26097. doi: 10.1002/jia2.26097.
  28. Strengthening sexual and reproductive health for diverse populations. IAS 2023, OAC04.
  29. Wu L et al. No association between in-utero PrEP exposure and bone mineral density at 36 months of age among mother-infant pairs in Kenya. IAS 2023, oral abstract OAC0402.
  30. Ngumbau N.M. et al. Cofactors of HIV self-testing and PrEP acceptance among pregnant women at high risk of HIV in Kenya. IAS 2023, oral abstract OAC0403.
  31. Lyons C et al. Experiences of reproductive coercion among women living with HIV in sub-Saharan Africa, eastern Europe and Central Asia. IAS 2023, oral abstract OAC0405.
  32. Hiransuthikul A et al. Drug-drug interaction between emtricitabine/tenofovir alafenamide (FTC/TAF)-based PrEP and feminizing hormones in transgender women: peripheral blood mononuclear cells and urine analysis from the iFACT3 study. IAS 2023, abstract OAC0404.
  33. Human-centred approaches. IAS 2023, OALBC06.
  34. Delany-Moretlwe S et al. Initial PrEP product choice: results from the HPTN 084 open-label extension. IAS 2023, oral abstract OALBX0203.

This report was first published on 15 August 2023.

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