In the Journals

Molecular epidemiology sheds light on HIV transmission network in LA

Researchers used public health data to reconstruct the HIV transmission network among transgender women in Los Angeles and said the approach could be useful to guide intervention efforts.

A phylogenic analysis showed that transgender women “tended to be part of the same clusters,” and that they clustered with men who have sex with men (MSM) less than expected, and with non-MSM cisgender men more than expected, researchers explained in The Lancet HIV.

“The way in which people are connected through the genetic transmission network provides information on transmission patterns within the population,” Manon Ragonnet-Cronin, PhD, of the department of medicine at the University of California, San Diego, and colleagues wrote.

“Transmission clusters comprising at least one transgender woman are attractive targets for interventions aimed at finding additional undiagnosed and at-risk transgender women, because individuals within that cluster are more likely to have other transgender women among their sexual or social contact networks.”

For their study, Ragonnet-Cronin and colleagues used the HIV-TRAnsmission Cluster Engine to identify a molecular transmission network from HIV protease and reverse transcriptase gene (pol) sequences available through the Los Angeles County public health department.

Data was available for 22,398 individuals, including 412 self-identified transgender women. According to Ragonnet-Cronin and colleagues, an analysis showed that 8,133 of the 22,398 individuals clustered in the network across 1,722 molecular transmission clusters.

The analysis found that transgender women who indicated a sexual risk factor clustered at the highest frequency in the network, with 43% being linked to at least one other person, the researchers reported.

“Transgender women were assortative in the network ... indicating that they tended to link to other transgender women,” they wrote. Moreover, the researchers said transgender women were more likely than expected to link to other transgender women (OR = 4.65) and to cisgender men who did not identify as MSM (OR = 1.53), and less likely than expected to cluster with MSM (OR = 0.75) “despite the high prevalence of HIV among MSM.”

The researchers said transgender women “occupy a distinct position” in the local transmission network and that the cluster patterns revealed by the analysis “suggest a potentially powerful strategy for using the molecular transmission network to improve public health outcomes.”

“Transgender women tended to be part of the same clusters, indicating linkage either directly or through shared partners,” they concluded. “This assortativity highlights the potential to use molecular epidemiology both to identify transmission clusters that are likely to include undiagnosed or undisclosed HIV-infected transgender women and to improve public health prevention and treatment activities.” – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.

Researchers used public health data to reconstruct the HIV transmission network among transgender women in Los Angeles and said the approach could be useful to guide intervention efforts.

A phylogenic analysis showed that transgender women “tended to be part of the same clusters,” and that they clustered with men who have sex with men (MSM) less than expected, and with non-MSM cisgender men more than expected, researchers explained in The Lancet HIV.

“The way in which people are connected through the genetic transmission network provides information on transmission patterns within the population,” Manon Ragonnet-Cronin, PhD, of the department of medicine at the University of California, San Diego, and colleagues wrote.

“Transmission clusters comprising at least one transgender woman are attractive targets for interventions aimed at finding additional undiagnosed and at-risk transgender women, because individuals within that cluster are more likely to have other transgender women among their sexual or social contact networks.”

For their study, Ragonnet-Cronin and colleagues used the HIV-TRAnsmission Cluster Engine to identify a molecular transmission network from HIV protease and reverse transcriptase gene (pol) sequences available through the Los Angeles County public health department.

Data was available for 22,398 individuals, including 412 self-identified transgender women. According to Ragonnet-Cronin and colleagues, an analysis showed that 8,133 of the 22,398 individuals clustered in the network across 1,722 molecular transmission clusters.

The analysis found that transgender women who indicated a sexual risk factor clustered at the highest frequency in the network, with 43% being linked to at least one other person, the researchers reported.

“Transgender women were assortative in the network ... indicating that they tended to link to other transgender women,” they wrote. Moreover, the researchers said transgender women were more likely than expected to link to other transgender women (OR = 4.65) and to cisgender men who did not identify as MSM (OR = 1.53), and less likely than expected to cluster with MSM (OR = 0.75) “despite the high prevalence of HIV among MSM.”

The researchers said transgender women “occupy a distinct position” in the local transmission network and that the cluster patterns revealed by the analysis “suggest a potentially powerful strategy for using the molecular transmission network to improve public health outcomes.”

“Transgender women tended to be part of the same clusters, indicating linkage either directly or through shared partners,” they concluded. “This assortativity highlights the potential to use molecular epidemiology both to identify transmission clusters that are likely to include undiagnosed or undisclosed HIV-infected transgender women and to improve public health prevention and treatment activities.” – by Caitlyn Stulpin

Disclosures: The authors report no relevant financial disclosures.