In the USA, the UK as well as several other European countries, HIV/AIDS has affected homosexuals more than any other demographic. In 2007 for example, it was estimated that about 255,000 gay men in the US were living with HIV/AIDS and around 5,400 had died (5). In the UK, about 48% of all those diagnosed with HIV/AIDS during the same period had been exposed to the virus through homosexuality (11). The results presented by Thailand Ministry of Health shows that there was a 100% increase in HIV prevalence among MSM across Western Europe (2). Thus, HIV/AIDS prevention programs have often targeted men who have sex with men (MSM). Despite the decrease in HIV-associated mortality rates that has been witnessed in developed and developing countries due to increased access to combination antiretroviral treat (cART) (7), this group still remains at risk. cART lowers the plasma viral load which determines the rate of HIV transmission from already infected people (9). de Wolf, Garnett, Hallett and Smit believe that even though starting early treatment is necessary to improve clinical outcomes, this group receiving treatment risks spreading the virus to those not affected (8). As such, this group is key determinant of HIV/AIDS prevalence across the globe. This paper examines the chances of HIV transmission from gay men receiving treatment to their sex partners, who are also men.
Importance of the study
The study examined the risk of HIV transmission from MSM who are on treatment to their male partners. It studied MSM transmission trends in Netherlands by analyzing in-depth data on the trends of viral load among this group, who pose the risk of increasing HIV/AIDS prevalence within the subpopulation as well as other demographics.
Given the statistics presented by the Centers for Disease Control and Prevention, MSM receiving treatment remain at high risk of transmitting HIV to their male sex partners who are not yet affected, especially among those living in the US, the UK and other developed European countries (2). Therefore, examining HIV transmission among MSM receiving treatment is significant in advancing public health HIV intervention programs. The study provides important statistics which is useful in planning and implementing HIV prevention programs, particularly in the developed world such as the US and most European countries where homosexuality is on the increasing trend.
Key study Conclusions
The study reaches the following conclusions (8):
In general, male partners to MSM receiving treatment are at risk of contracting HIV virus although the risk is relative to condom use as well as the last time of viral load detection.
The study reports that if condoms are not used at all during sexual intercourse between MSM and their partners, then the risk of HIV transmission is about 22%. The risk of transmission is 47% when Plasma viral load has not been suppressed. MSM receiving treatment pose HIV transmission risk of 9-37% to their male sex partners. Chapman, de Wolf, Fraser, Hannage and Hollingsworth explain that this occurs when the viral load has not been suppressed sufficiently regardless of whether the regimen is quickly changed or not or when the viral load rebounds quickly and reaches high levels before it is detected (6).
30% condoms use can lower HIV transmission risk by about 17%. Using the uncertainty analysis, the risk ranges between 7% and 29%. It further concludes that MSM receiving treatment who maintain condom use except in cases where their viral load was not detected at the last measurement in the preceding 6 months, pose transmission risk of just 3%. The low risk is achieved because the risk generating factors explained by Chapman et al are eliminated (6).
The study also concludes that the likelihood of gay male under treatment transferring the virus to a partner increases by about 2% when all patients are closely monitored. This risk increases to 5% when about 20% of the patients receiving treatment do not return for care. The study concludes that patients receiving treatment have to be frequently monitored to reduce the chances of HIV transmission since patients monitored regularly have a chance of being switched to new regimens should the first-line treatment fail.
Does the data justify the conclusions?
The data used in this study justifies the key conclusions presented above. The viral load trends that were used were obtained from detailed data recovered from ATHENA observational cohort of HIV-infected persons across Netherlands. These data were used to evaluate cohorts of MSM in the Netherlands, and this makes the findings of the study to be statistically valuable. The contribution of MSM in HIV/AIDS as presented in this study may explain the increasing HIV prevalence among MSM.
Strengths of the study
The key strengths of the study include (8):
Sample size
The data analyzed in the study was collected from ATHENA which provided viral load trends among MSM across Netherlands. Thus, the result can be used to make reliable generalizations on HIV transmission risk in developed countries where the risk is relatively similar to that of the Netherlands.
Study design
The data that was used in the study captured changes over time in three distinct trajectories. Thus it showed varying possibilities of viral load evolution in MSM receiving treatment. As a result, the study was able to make conclusions on the relationship between monitoring of patients receiving treatment and HIV transmission risk.
The study was a continuation of an earlier work on the same, and therefore, the results were used to develop a stochastic individual-based simulation model of patient monitoring, HIV transmission risk as well as viral load trends for cohorts of MSM across the country. This improved reliability of the findings.
Weakness of the study
During the research process, several simplifying assumptions were made. It was assumed that below a certain level of viral load, the possibility of HIV transmission is low; however, there is no evidence to prove whether the chances are zero or actually low (1). In addition, the study assumed that the risk of HIV transmission for every sex activity can be scaled to equal just an approximate observation of the risk. However, it did not consider differences in frequency of being the “woman” or “man” (3-4).
Simulation model
The stochastic simulation model developed in the study did not incorporate the effects that other STIs would have on HIV transmission. Thus, STI influence on HIV transmission among MSM was not analyzed, and as a result, it did not allow for complete exploration of factors likely to influence HIV transmission in this group.
During the model design, it was assumed that the influence of intermittent viraemia on the risk of HIV transmission in this group is relatively low. However, there is no evidence to prove this (11).
Implications of the study
The facts presented in the study have demonstrated that patient monitoring among MSM receiving treatment should be strengthened. Viral load not detected on time could expose partners to those in this group to high risk of infection. This means that intervention strategies should focus on encouraging MSM receiving treatment to continue coming for care services.
How can the study be built upon?
This study is incomplete without finding out the effects of other STIs on HIV infection among MSM and their partners. Further research should therefore focus on the patterns of STI prevalence among this group so as to be able to understand the overall estimates of HIV transmission among MSM.
Conclusion
The study shows significant HIV transmission risk from MSM receiving treatment to their partners. As such, the frequency of monitoring of patients in this group should be increased.
References
Attia S, Egger M, Low N, Muller M & Zwahlen M. Sexual transmission of HIV according to viral load and antiretroviral therapy: systematic review and meta-analysis. AIDS. 2009: 23:1397-1404.
Baraf S, Grulich A, van Griensven F, Van Wijingaarden L & Willem J. The global epidemic of HIV infection among men who have sex with men. Nonthaburi: Thailand Ministry of Public Health. 2009.
Buchbinder SP, Douglas J, Judson F, MacQueen K, McKiman D & Vittinghoff E. Per-contact risk of human immunodeficiency virus transmission between male sexual partners. American Journal of Epidemiology. 1999; 150:306-311.
Barresi PJ, Celum CL, Colfax G, Huang Y, Husnik MJ, Koblin BA, Madison M & Mayer K.. Risk factors for HIV infection among men who have sex with men. Aids 2006; 20:731-739.
Centers for Disease Control and Prevention. Cases of HIV infection and AIDS in the United States and dependent areas. HIV/AIDS Surveillance Report. 2007; 19.
Chapman R, de Wolf F, Fraser C, Hannage WP & Hollingsworth TD, Chapman R. Variation in HIV-1 set-point viral load: epidemiological analysis and an evolutionary hypothesis. Proceedings of the National Academy of Science of the United States of America. 2007; 104:17441-17446.
Currier JS, Demeter LM, Grimes JM, Hammer SM, Hughes MD & Squires KE. A controlled trial of two nucleoside analogues plus indinavir in persons with human immunodeficiency virus infection and CD4 cell counts of 200 per cubic millimeter or less. AIDS Clinical Trials Group 320 Study Team. The New England Journal of Medicine. 1997; 337:725-733.
de Wolf F, Garnett GP, Hallett TB & Smit C. Estimating the risk of HIV transmission from homosexual men receiving treatment to their HIV-uninfected partners. Sexually Transmitted Infections 2011; 87:17-21.
Gray RH, Li C, Lutalo T, Meehan MO, Quinn TC, Serwadda D, Sewankambo N, Wabwire-Mangen F & Wawer MJ. Viral load and heterosexual transmission of human immunodeficiency virus type 1. Rakai Project Study Group. The New England Journal of Medicine. 2000; 342:921-929.
Hanna GJ, Podsadecki TJ, Rode RA, Tousset EP & Vrijens BC. Decreased adherence to antiretroviral therapy observed prior to transient human immunodeficiency virus type 1 viremia. Journal of Infectious Diseases. 2007; 196:1773-1778.
Health Protection Agency Centre for Infections and Health Protection Scotland. Unpublished HIV Diagnoses Surveillance Tables [Internet]. 2009. Web.