Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation

Virginie Mortier; Laurent Debaisieux; Deborah De Geyter; Marie-Luce Delforge; Melissa Depypere; Geraldine Dessilly; Benoit Kabamba-Mukadi; Khalid El Moussaoui; Samy Mzougui; Ben Serrien; Karolien Stoffels; Dominique Van Beckhoven; Ellen Van Cutsem; Dorien van den Bossche; Sigi van den Wijngaert; Fien Vanroye; Elizaveta Padalko; Chris Verhofstede; Kristel Van Laethem

doi:10.3390/v18050554

Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation

Virginie Mortier
, Laurent Debaisieux
, Deborah De Geyter
, Marie-Luce Delforge
, Melissa Depypere
, Geraldine Dessilly
, Benoit Kabamba-Mukadi
, Khalid El Moussaoui
, Samy Mzougui
, Ben Serrien
, Karolien Stoffels
, Dominique Van Beckhoven
, Ellen Van Cutsem
, Dorien van den Bossche
, Sigi van den Wijngaert
, Fien Vanroye
, Elizaveta Padalko
, Chris Verhofstede
, Kristel Van Laethem

Clinical Reference Laboratory

Research output: Contribution to journal › A1: Peer-reviewed journal articles › peer-review

Abstract

The international spread of HIV-1 sub-subtype A6 raises concerns due to its association with contraindications for long-acting injectable formulations of cabotegravir (LA-CAB) and rilpivirine (LA-RPV). This study investigated its increasing proportion in Belgium, assessing transmission dynamics and potential migration links. Additionally, genotypic drug resistance in the Belgian HIV-1 sub-subtype A6 population were analyzed and four automatic subtyping tools were compared. A dataset of 4764 HIV-1 protease and reverse transcriptase (RT) sequences from newly diagnosed, treatment-na & iuml;ve individuals in Belgium (2013-2022) was analyzed. A combination of phylogenetic analysis and online subtyping tools identified 136 sub-subtype A6 sequences. The increase in the proportion of HIV-1 sub-subtype A6 observed in Belgium since 2020 reflects changing transmission patterns, especially among Belgium-born men having sex with men, and cannot be solely linked to the recent influx of Ukrainian migrants. Of these sub-subtype A6 sequences, less than 10% showed LA-CAB + LA-RPV resistance, mainly due to E138A within RT. HIVdb and ANRS reliably assessed resistance in this therapy-na & iuml;ve cohort, and HIVdb, COMET, and SmartGene (R) produced concordant subtyping results. While algorithm choice has little impact at low resistance prevalence, further research is necessary and HIVdb and ANRS remain more suitable for ongoing clinical and research use.

Original language	English
Article number	554
Journal	Viruses-Basel
Volume	18
Issue number	5
Number of pages	13
ISSN	1999-4915
DOIs	https://doi.org/10.3390/v18050554
Publication status	Published - 12-May-2026

Keywords

Genotypic drug resistance
Human immunodeficiency virus
sub-subtype A6
Subtyping tools
Transmission dynamics
Humans
HIV Protease/genetics
Genotype
Male
Phylogeny
Belgium/epidemiology
Drug Resistance, Viral/genetics
HIV-1/genetics
HIV Infections/transmission
Female
HIV Reverse Transcriptase/genetics
Anti-HIV Agents/pharmacology

Access to Document

10.3390/v18050554Licence: CC BY

Cite this

Mortier, V., Debaisieux, L., De Geyter, D., Delforge, M.-L., Depypere, M., Dessilly, G., Kabamba-Mukadi, B., El Moussaoui, K., Mzougui, S., Serrien, B., Stoffels, K., Van Beckhoven, D., Van Cutsem, E., van den Bossche, D., van den Wijngaert, S., Vanroye, F., Padalko, E., Verhofstede, C., & Van Laethem, K. (2026). Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation. Viruses-Basel, 18(5), Article 554. https://doi.org/10.3390/v18050554

@article{2c107698436b41b3a8a537c748263787,

title = "Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation",

abstract = "The international spread of HIV-1 sub-subtype A6 raises concerns due to its association with contraindications for long-acting injectable formulations of cabotegravir (LA-CAB) and rilpivirine (LA-RPV). This study investigated its increasing proportion in Belgium, assessing transmission dynamics and potential migration links. Additionally, genotypic drug resistance in the Belgian HIV-1 sub-subtype A6 population were analyzed and four automatic subtyping tools were compared. A dataset of 4764 HIV-1 protease and reverse transcriptase (RT) sequences from newly diagnosed, treatment-na \& iuml;ve individuals in Belgium (2013-2022) was analyzed. A combination of phylogenetic analysis and online subtyping tools identified 136 sub-subtype A6 sequences. The increase in the proportion of HIV-1 sub-subtype A6 observed in Belgium since 2020 reflects changing transmission patterns, especially among Belgium-born men having sex with men, and cannot be solely linked to the recent influx of Ukrainian migrants. Of these sub-subtype A6 sequences, less than 10\% showed LA-CAB + LA-RPV resistance, mainly due to E138A within RT. HIVdb and ANRS reliably assessed resistance in this therapy-na \& iuml;ve cohort, and HIVdb, COMET, and SmartGene (R) produced concordant subtyping results. While algorithm choice has little impact at low resistance prevalence, further research is necessary and HIVdb and ANRS remain more suitable for ongoing clinical and research use.",

keywords = "Genotypic drug resistance, Human immunodeficiency virus, sub-subtype A6, Subtyping tools, Transmission dynamics, Humans, HIV Protease/genetics, Genotype, Male, Phylogeny, Belgium/epidemiology, Drug Resistance, Viral/genetics, HIV-1/genetics, HIV Infections/transmission, Female, HIV Reverse Transcriptase/genetics, Anti-HIV Agents/pharmacology",

author = "Virginie Mortier and Laurent Debaisieux and \{De Geyter\}, Deborah and Marie-Luce Delforge and Melissa Depypere and Geraldine Dessilly and Benoit Kabamba-Mukadi and \{El Moussaoui\}, Khalid and Samy Mzougui and Ben Serrien and Karolien Stoffels and \{Van Beckhoven\}, Dominique and \{Van Cutsem\}, Ellen and \{van den Bossche\}, Dorien and \{van den Wijngaert\}, Sigi and Fien Vanroye and Elizaveta Padalko and Chris Verhofstede and \{Van Laethem\}, Kristel",

note = "FTX: CC BY",

year = "2026",

month = may,

day = "12",

doi = "10.3390/v18050554",

language = "English",

volume = "18",

journal = "Viruses-Basel",

issn = "1999-4915",

publisher = "Multidisciplinary Digital Publishing Institute (MDPI)",

number = "5",

}

Mortier, V, Debaisieux, L, De Geyter, D, Delforge, M-L, Depypere, M, Dessilly, G, Kabamba-Mukadi, B, El Moussaoui, K, Mzougui, S, Serrien, B, Stoffels, K, Van Beckhoven, D, Van Cutsem, E, van den Bossche, D, van den Wijngaert, S, Vanroye, F, Padalko, E, Verhofstede, C & Van Laethem, K 2026, 'Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation', Viruses-Basel, vol. 18, no. 5, 554. https://doi.org/10.3390/v18050554

TY - JOUR

T1 - Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation

AU - Mortier, Virginie

AU - Debaisieux, Laurent

AU - De Geyter, Deborah

AU - Delforge, Marie-Luce

AU - Depypere, Melissa

AU - Dessilly, Geraldine

AU - Kabamba-Mukadi, Benoit

AU - El Moussaoui, Khalid

AU - Mzougui, Samy

AU - Serrien, Ben

AU - Stoffels, Karolien

AU - Van Beckhoven, Dominique

AU - Van Cutsem, Ellen

AU - van den Bossche, Dorien

AU - van den Wijngaert, Sigi

AU - Vanroye, Fien

AU - Padalko, Elizaveta

AU - Verhofstede, Chris

AU - Van Laethem, Kristel

N1 - FTX: CC BY

PY - 2026/5/12

Y1 - 2026/5/12

N2 - The international spread of HIV-1 sub-subtype A6 raises concerns due to its association with contraindications for long-acting injectable formulations of cabotegravir (LA-CAB) and rilpivirine (LA-RPV). This study investigated its increasing proportion in Belgium, assessing transmission dynamics and potential migration links. Additionally, genotypic drug resistance in the Belgian HIV-1 sub-subtype A6 population were analyzed and four automatic subtyping tools were compared. A dataset of 4764 HIV-1 protease and reverse transcriptase (RT) sequences from newly diagnosed, treatment-na & iuml;ve individuals in Belgium (2013-2022) was analyzed. A combination of phylogenetic analysis and online subtyping tools identified 136 sub-subtype A6 sequences. The increase in the proportion of HIV-1 sub-subtype A6 observed in Belgium since 2020 reflects changing transmission patterns, especially among Belgium-born men having sex with men, and cannot be solely linked to the recent influx of Ukrainian migrants. Of these sub-subtype A6 sequences, less than 10% showed LA-CAB + LA-RPV resistance, mainly due to E138A within RT. HIVdb and ANRS reliably assessed resistance in this therapy-na & iuml;ve cohort, and HIVdb, COMET, and SmartGene (R) produced concordant subtyping results. While algorithm choice has little impact at low resistance prevalence, further research is necessary and HIVdb and ANRS remain more suitable for ongoing clinical and research use.

AB - The international spread of HIV-1 sub-subtype A6 raises concerns due to its association with contraindications for long-acting injectable formulations of cabotegravir (LA-CAB) and rilpivirine (LA-RPV). This study investigated its increasing proportion in Belgium, assessing transmission dynamics and potential migration links. Additionally, genotypic drug resistance in the Belgian HIV-1 sub-subtype A6 population were analyzed and four automatic subtyping tools were compared. A dataset of 4764 HIV-1 protease and reverse transcriptase (RT) sequences from newly diagnosed, treatment-na & iuml;ve individuals in Belgium (2013-2022) was analyzed. A combination of phylogenetic analysis and online subtyping tools identified 136 sub-subtype A6 sequences. The increase in the proportion of HIV-1 sub-subtype A6 observed in Belgium since 2020 reflects changing transmission patterns, especially among Belgium-born men having sex with men, and cannot be solely linked to the recent influx of Ukrainian migrants. Of these sub-subtype A6 sequences, less than 10% showed LA-CAB + LA-RPV resistance, mainly due to E138A within RT. HIVdb and ANRS reliably assessed resistance in this therapy-na & iuml;ve cohort, and HIVdb, COMET, and SmartGene (R) produced concordant subtyping results. While algorithm choice has little impact at low resistance prevalence, further research is necessary and HIVdb and ANRS remain more suitable for ongoing clinical and research use.

KW - Genotypic drug resistance

KW - Human immunodeficiency virus

KW - sub-subtype A6

KW - Subtyping tools

KW - Transmission dynamics

KW - Humans

KW - HIV Protease/genetics

KW - Genotype

KW - Male

KW - Phylogeny

KW - Belgium/epidemiology

KW - Drug Resistance, Viral/genetics

KW - HIV-1/genetics

KW - HIV Infections/transmission

KW - Female

KW - HIV Reverse Transcriptase/genetics

KW - Anti-HIV Agents/pharmacology

UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=itm_wosliteitg&SrcAuth=WosAPI&KeyUT=WOS:001775444100001&DestLinkType=FullRecord&DestApp=WOS_CPL

U2 - 10.3390/v18050554

DO - 10.3390/v18050554

M3 - A1: Peer-reviewed journal articles

C2 - 42198757

SN - 1999-4915

VL - 18

JO - Viruses-Basel

JF - Viruses-Basel

IS - 5

M1 - 554

ER -

Emerging Trends in HIV-1 Sub-Subtype A6 in Belgium: Transmission Dynamics, Drug Resistance, and Subtyping Tool Evaluation

Abstract

Keywords

Access to Document

Other files and links

Fingerprint

Cite this