Editing HIV (section)

== Treatment and transmission==
{{Main|Management of HIV/AIDS}}{{See also|1=HIV/AIDS#Transmission|2=Undetectable = Untransmittable}}
The management of HIV/AIDS typically involves the use of multiple [[antiretroviral drugs]]. In many parts of the world, HIV has become a chronic condition, with progression to [[AIDS]] increasingly rare.

[[HIV latency]] and the resulting [[viral reservoir]] in CD4<sup>+</sup> T cells, dendritic cells, and macrophages is the main barrier to eradication of the virus.<ref name="HIV Latency" /><ref name="Rodari">{{cite journal |last1=Rodari |first1=Anthony |last2=Darcis |first2=Gilles |last3=Van Lint |first3=Carine M. |date=29 September 2021 |title=The Current Status of Latency Reversing Agents for HIV-1 Remission |journal=Annual Review of Virology |language=en |volume=8 |issue=1 |pages=491–514 |doi=10.1146/annurev-virology-091919-103029 |issn=2327-056X |pmid=34586875 |doi-access=free}}</ref>

While HIV is highly virulent, transmission through sexual contact does not occur when an HIV-positive individual maintains a consistently undetectable [[viral load]] (<50 copies/ml) due to antiretroviral treatment. This concept was first proposed by the Swiss Federal Commission for AIDS/HIV in 2008 in what is known as the [[Swiss Statement]].<ref>{{cite web |author=Swiss National AIDS Commission |date=15 October 2016 |title=The Swiss statement |url=http://i-base.info/qa/factsheets/the-swiss-statement |access-date=2 April 2019 |publisher=[[HIV i-Base]]}}</ref><ref name="Vernazza&Bernard">{{cite journal |vauthors=Vernazza P, Bernard EJ |date=29 January 2016 |title=HIV is not transmitted under fully suppressive therapy: The Swiss Statement—eight years later |journal=[[Swiss Medical Weekly]] |volume=146 |pages=w14246 |doi=10.4414/smw.2016.14246 |pmid=26824882 |doi-access=free}}</ref> Although initially controversial, subsequent studies have confirmed that the risk of transmitting HIV through sex is effectively zero when the HIV-positive person has a consistently undetectable viral load, a concept now widely known as U=U, or "Undetectable = Untransmittable."<ref>{{cite journal |author=The Lancet HIV |date=November 2017 |title=U=U taking off in 2017 |department=Editorial |journal=The Lancet. HIV |volume=4 |issue=11 |pages=e475 |doi=10.1016/S2352-3018(17)30183-2 |pmid=29096785 |doi-access=free}}</ref><ref>{{cite web |year=2019 |title=Can't Pass It On |url=https://www.tht.org.uk/our-work/our-campaigns/cant-pass-it-on |url-status=live |archive-url=https://web.archive.org/web/20190407233322/https://www.tht.org.uk/our-work/our-campaigns/cant-pass-it-on |archive-date=7 April 2019 |access-date=2 April 2019 |publisher=[[Terrence Higgins Trust]]}}</ref>

Studies that established the U=U principle include Opposites Attract,<ref name="Opposites Attract">{{cite journal | vauthors = Bavinton BR, Pinto AN, Phanuphak N, Grinsztejn B, Prestage GP, Zablotska-Manos IB, Jin F, Fairley CK, Moore R, Roth N, Bloch M, Pell C, McNulty AM, Baker D, Hoy J, Tee BK, Templeton DJ, Cooper DA, Emery S, Kelleher A, Grulich AE | display-authors = 6 | title = Viral suppression and HIV transmission in serodiscordant male couples: an international, prospective, observational, cohort study | journal = The Lancet. HIV | volume = 5 | issue = 8 | pages = e438–e447 | date = August 2018 | pmid = 30025681 | doi = 10.1016/S2352-3018(18)30132-2 | s2cid = 51702998 }}</ref> PARTNER 1,<ref name="PARTNER1">{{cite journal | vauthors = Rodger AJ, Cambiano V, Bruun T, Vernazza P, Collins S, van Lunzen J, Corbelli GM, Estrada V, Geretti AM, Beloukas A, Asboe D, Viciana P, Gutiérrez F, Clotet B, Pradier C, Gerstoft J, Weber R, Westling K, Wandeler G, Prins JM, Rieger A, Stoeckle M, Kümmerle T, Bini T, Ammassari A, Gilson R, Krznaric I, Ristola M, Zangerle R, Handberg P, Antela A, Allan S, Phillips AN, Lundgren J | display-authors = 6 | title = Sexual Activity Without Condoms and Risk of HIV Transmission in Serodifferent Couples When the HIV-Positive Partner Is Using Suppressive Antiretroviral Therapy | journal = JAMA | volume = 316 | issue = 2 | pages = 171–81 | date = July 2016 | pmid = 27404185 | doi = 10.1001/jama.2016.5148 | doi-access = free }}</ref> PARTNER 2<ref name="PARTNER2-2019" /><ref name="PARTNER2">{{cite conference|last=Rodger |first= A. (for the PARTNER study group) |title=Risk of HIV transmission through condomless sex in MSM couples with suppressive ART: The PARTNER2 Study extended results in gay men |conference=AIDS2018: 22nd International AIDS Conference |location=Amsterdam, the Netherlands |date=July 2018 |url=https://programme.aids2018.org/Abstract/Abstract/13470 |access-date=2 April 2019}}</ref> (which focused on male-male couples),<ref name="Hoffman">{{cite press release |title=The science is clear: with HIV, undetectable equals untransmittable |date=10 January 2019 |publisher=[[National Institutes of Health]] |url=https://www.nih.gov/news-events/news-releases/science-clear-hiv-undetectable-equals-untransmittable |quote=NIAID Director Anthony S. Fauci, M.D., and colleagues summarize results from large clinical trials and cohort studies validating U=U. The landmark NIH-funded HPTN 052 clinical trial showed that no linked HIV transmissions occurred among HIV serodifferent heterosexual couples when the partner living with HIV had a durably suppressed viral load. Subsequently, the PARTNER and Opposites Attract studies confirmed these findings and extended them to male-male couples. ... The success of U=U as an HIV prevention method depends on achieving and maintaining an undetectable viral load by taking ART daily as prescribed. |access-date=3 May 2019 |vauthors=Hoffman H |agency=[[National Institute of Allergy and Infectious Diseases]]}}</ref> and [[HPTN 052|HPTN052]]<ref name="HPTN052">{{cite journal | vauthors = Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, Kumarasamy N, Hakim JG, Kumwenda J, Grinsztejn B, Pilotto JH, Godbole SV, Chariyalertsak S, Santos BR, Mayer KH, Hoffman IF, Eshleman SH, Piwowar-Manning E, Cottle L, Zhang XC, Makhema J, Mills LA, Panchia R, Faesen S, Eron J, Gallant J, Havlir D, Swindells S, Elharrar V, Burns D, Taha TE, Nielsen-Saines K, Celentano DD, Essex M, Hudelson SE, Redd AD, Fleming TR | display-authors = 6 | title = Antiretroviral Therapy for the Prevention of HIV-1 Transmission | journal = The New England Journal of Medicine | volume = 375 | issue = 9 | pages = 830–9 | date = September 2016 | pmid = 27424812 | pmc = 5049503 | doi = 10.1056/NEJMoa1600693 | doi-access = free | author-link1 = Myron S. Cohen }}</ref> (which focused on heterosexual couples).<ref name="Hoffman" /> These studies involved couples where one partner was HIV-positive and one was HIV-negative, and included regular HIV testing. Across these four studies, a total of 4,097 couples participated from four continents, reporting 151,880 acts of condomless sex with zero phylogenetically-linked HIV transmissions when the positive partner had an undetectable viral load.<ref>{{cite conference | vauthors = Hodson M |title=U=U: Talking to patients about transmission risk |conference=British HIV Association Autumn Conference 2017 |date=17 November 2017 |url=https://www.bhiva.org/file/iGHaSOpwVeAQY/MatthewHodson.pdf |access-date=3 May 2019}} ([https://www.bhiva.org/171117MatthewHodson abstract] for presentation on behalf of [[NAM Aidsmap|NAM / Aidsmap]])</ref> Following these findings, the U=U consensus statement advocating the use of the term 'zero risk' was endorsed by numerous individuals and organizations, including the [[CDC]], the [[British HIV Association]], and ''[[The Lancet]]'' medical journal.<ref>{{cite web |publisher=[[Prevention Access Campaign]] |title=Consensus statement: Risk of Sexual Transmission of HIV from a Person Living with HIV who has an Undetectable Viral Load |url=https://www.preventionaccess.org/consensus |date=21 July 2016 |access-date=2 April 2019}} '''Note''': When the statement and list of endorsements was retrieved, it had last been updated on 23 August 2018 and included "over 850 organizations from nearly 100 countries."</ref>

Additionally, reactivation of [[herpes simplex virus-2]] (HSV-2) in individuals with [[genital herpes]] is associated with an increase in [[CCR5|CCR-5]] enriched CD4<sup>+</sup> T cells and inflammatory dendritic cells in the dermis of ulcerated genital skin, persisting even after ulcer healing. HIV's tropism for CCR-5 positive cells contributes to the two- to threefold increased risk of HIV acquisition in persons with genital herpes. Notably, daily antiviral medication, such as [[acyclovir]], does not reduce the subclinical post-reactivation inflammation and therefore does not decrease the risk of HIV acquisition.<ref>{{cite journal | vauthors = Zhu J, Hladik F, Woodward A, Klock A, Peng T, Johnston C, Remington M, Magaret A, Koelle DM, Wald A, Corey L | display-authors = 6 | title = Persistence of HIV-1 receptor-positive cells after HSV-2 reactivation is a potential mechanism for increased HIV-1 acquisition | journal = Nature Medicine | volume = 15 | issue = 8 | pages = 886–92 | date = August 2009 | pmid = 19648930 | pmc = 2723183 | doi = 10.1038/nm.2006 }}</ref><ref>{{cite journal | vauthors = Looker KJ, Elmes JA, Gottlieb SL, Schiffer JT, Vickerman P, Turner KM, Boily MC | title = Effect of HSV-2 infection on subsequent HIV acquisition: an updated systematic review and meta-analysis | journal = The Lancet. Infectious Diseases | volume = 17 | issue = 12 | pages = 1303–1316 | date = December 2017 | pmid = 28843576 | pmc = 5700807 | doi = 10.1016/S1473-3099(17)30405-X }}</ref>