HIV-1 Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs) in Israel, 2010–2018

Tali Wagner*, Neta S. Zuckerman, Marina Wax, Rachel Shirazi, Yael Gozlan, Shirley Girshengorn, Rotem Marom, Ella Mendelson, Dan Turner, Orna Mor*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Monitoring HIV-1 circulating recombinant forms (CRFs) and unique recombinant forms (URFs) is important for disease surveillance. Recombination may affect prevention efforts and interfere with the diagnosis and treatment of HIV-1 infection. Here, we characterized the epidemiology of HIV-1 CRFs and URFs in Israel. Partial pol sequences from treatment naïve patients diagnosed in 2010–2018 were assessed using the recombinant identification program (RIP), the recombinant detection program (RDP5), and using the maximum-likelihood phylogenetic method, using 410 reference sequences obtained from the Los Alamos database. CRFs and URFs were identified in 11% (213/1940) of all sequenced cases. The median age at diagnosis was 38 (30–47) years, 61% originated from Israel, and 82% were male. The most common were CRF02_AG (30.5%), CRF01_AE (16.9%), and the more complex forms CRF01_AE/CRF02_AG/A3 (10.8%) and B/F1 (7%). A significant increase in their overall proportion was observed in recent years (8.1% in 2010–2012, 20.3% in 2016–2018, p < 0.001). This increase was most prominent in individuals carrying CRF02_AG (2.5% in 2010–2015, 9.8% in 2016–2018, p < 0.001). Men who have sex with men (MSM) was the most common risk group; however, those infected with the secondary recombinant CRF02_AG/A6 were mainly injecting drug users (IDUs). The most common resistance mutations were K103N (5/213, 2.3%) and E138A (18/213, 8.5%) in the reverse transcriptase. Only E138A was more frequent in the recombinants compared with the classic subtypes and was significantly associated with a specific secondary CRF, CRF02_AG/A4. We concluded that CRFs and URFs were mainly detected in Israeli-born MSM and that an increase in the overall proportion of such HIV-1 sequences could be observed in more recent years.

Original languageEnglish
Article number1970
Issue number9
StatePublished - Sep 2022


  • HIV-1 drug resistance mutations (HIVdrm)
  • HIV-1 inter-subtype diversity
  • circulating recombinant forms (CRFs)
  • epidemiology
  • transmitted drug resistance mutations (TDRM)


Dive into the research topics of 'HIV-1 Circulating Recombinant Forms (CRFs) and Unique Recombinant Forms (URFs) in Israel, 2010–2018'. Together they form a unique fingerprint.

Cite this