Non-disclosed men who have sex with men in UK HIV transmission networks

[Jim Allen]

In short what i get from this is they analysed the genetic code of the virus from HIV-positive people and came to the conclusion that some of the self-reported heterosexual mens HIV was more than likely actually non-disclosed MSM.

Well I think its fair to say or at least my thinking always was that self-reported data should be taken with a liberal pitch of salt. Plenty of reasons people don't disclose sexuality, risks or true transmission routes.     .

Non-disclosed men who have sex with men in UK HIV transmission networks: phylogenetic analysis of surveillance data


https://www.thelancet.com/journals/lanhiv/article/PIIS2352-3018(18)30062-6/fulltext

Background
Patients who do not disclose their sexuality, including men who do not disclose same-sex behaviour, are difficult to characterise through traditional epidemiological approaches such as interviews. Using a recently developed method to detect large networks of viral sequences from time-resolved trees, we localised non-disclosed men who have sex with men (MSM) in UK transmission networks, gaining crucial insight into the behaviour of this group.

Methods
For this phylogenetic analysis, we obtained HIV pol sequences from the UK HIV Drug Resistance Database (UKRDB), a central repository for resistance tests done as part of routine clinical care throughout the UK. Sequence data are linked to demographic and clinical data held by the UK Collaborative HIV Cohort study and the national HIV/AIDS reporting system database. Initially, we reconstructed maximum likelihood phylogenies from these sequences, then sequences were selected for time-resolved analysis in BEAST if they were clustered with at least one other sequence at a genetic distance of 4·5% or less with support of at least 90%. We used time-resolved phylogenies to create networks by linking together nodes if sequences shared a common ancestor within the previous 5 years. We identified potential non-disclosed MSM (pnMSM), defined as self-reported heterosexual men who clustered only with men. We measured the network position of pnMSM, including betweenness (a measure of connectedness and importance) and assortativity (the propensity for nodes sharing attributes to link).

Findings
14 405 individuals were in the network, including 8452 MSM, 1743 heterosexual women and 1341 heterosexual men. 249 pnMSM were identified (18·6% of all clustered heterosexual men) in the network. pnMSM were more likely to be black African (p<0·0001), less likely to be infected with subtype B (p=0·006), and were slightly older (p=0·002) than the MSM they clustered with. Mean betweenness centrality was lower for pnMSM than for MSM (1·31, 95% CI 0·48–2·15 in pnMSM vs 2·24, 0·98–3·51 in MSM; p=0·002), indicating that pnMSM were in peripheral positions in MSM clusters. Assortativity by risk group was higher than expected (0·037 vs −0·037, p=0·01) signifying that pnMSM were linked to each other. We found that self-reported heterosexual men were more likely to link MSM and heterosexual women than heterosexual women were to link MSM and heterosexual men (Fisher's exact test p=0·0004; OR 2·24) but the number of such transmission chains was small (only 54 in total vs 32 in women).

Interpretation
pnMSM are a subgroup distinct from both MSM and from heterosexual men. They are more likely to choose sexual partners who are also pnMSM and might exhibit lower-risk sexual behaviour than MSM (eg, choosing low-risk partners or consistently using condoms). Heterosexual men are the group most likely to be diagnosed with late-stage disease (ie, low CD4 counts) and non-disclosed MSM might put female partners at higher risk than heterosexual men because non-disclosed MSM have male partners. Hence, pnMSM require specific consideration to ensure they are included in public health interventions.

[CaveyUK]

It's obvious that a lot of people won't disclose real risk situations, for a multitude of reasons and we don't really need a study to tell us that.

That said, in terms of public intervention, targeting people who identify as heterosexual but who have had sex with men, is futile in my opinion. For a start, it is missing the group of people who identify as heterosexual and who DON'T have sex with men and secondly, the intended group may not be receptive to a message which they will have convinced themselves, doesn't apply to them.

I've long thought that a wider message which stresses that heterosexual people have just as much real-world risk as other groups is the best way, as it not only means the message reaches the correct audience but also helps de-stigmatise the condition in those who may have had same-sex dalliances in the past.

I understand the targeting of specific populations about HIV however I've always felt that communicating a message that implies that HIV is only a problem for men if they have had sex with other men, no matter how well intentioned, would actually set back efforts to encourage testing in those populations (as well as being factually inaccurate).

[Jim Allen]

Yeah, and I agree with the thought on casting a wider net so to speak in terms of HIV prevention & education so everyone is testing and practicing prevention.
Although i do understand targeted approach when funding is limited but targeting a small group that is in the closet or down low/non disclosed is highly difficult. 

I mean for Ireland as example the MSM community is disproportionately affected, so free testing is promoted in LGBT pubs & clubs, and than there is also free routine testing from STI clinics aimed at the MSM groups, this makes sense and within a  short few years as a group that community tends to be testing more frequent and being diagnosed sooner.

Its left heterosexual women & men somewhat behind in the sense that the group would have limited (free) testing opportunities and as a result those diagnosed had very low previous testing history before diagnosis, nearly non-existed with the heterosexual groups also as result being disproportionately diagnosed late & very late 86% under heterosexual women in 2016 & 2017 and 76% of heterosexual men. I think were seeing tip of the iceberg of what is coming down the stream for this group in my neck of the woods as they have been living with HIV unknown for some time and there is greater risk they passed it on.

Jim