{"id":5997,"date":"2024-06-01T12:00:29","date_gmt":"2024-06-01T12:00:29","guid":{"rendered":"http:\/\/i-base.info\/guides\/?page_id=5997"},"modified":"2024-09-29T10:05:37","modified_gmt":"2024-09-29T10:05:37","slug":"viral-load","status":"publish","type":"page","link":"https:\/\/i-base.info\/guides\/testing\/viral-load","title":{"rendered":"Viral load"},"content":{"rendered":"

\"\"<\/p>\n

Viral load is the most important factor in the risk of HIV. <\/strong><\/p>\n

U=U<\/a><\/strong> means that HIV cannot be transmitted if viral load is undetectable.<\/p>\n

So viral load is more important than condom use.<\/p>\n

Viral load determines how infectious bodily fluids are. Levels are highest in someone who is recently infected (up to 40 million copies in a millilitre of blood). By comparison, someone on treatment with an undetectable viral load has less than 50 copies\/mL (see Figures 2 and 3). [3]<\/p>\n

When viral load is very high, low risk activities like giving oral sex become a higher risk.<\/p>\n

If viral load is undetectable, there is zero risk of HIV.<\/strong><\/p>\n

PrEP<\/a> also protects against HIV, even when viral load is very high.<\/strong><\/p>\n

in 2014, the PARTNER study reported no linked HIV transmissions when viral load was undetectable.<\/p>\n

This was in 900 couples who had sex more than 58,000 times without using condoms. [1]<\/p>\n

Importantly, this study included gay couples and anal sex (gay and straight).<\/p>\n

It included periods when viral load was likely to blip between tests and when there were other STIs.<\/p>\n

In 2018, the PARTNER 2 study produced even more evidence to support the safety in gay men. This time, with no transmissions after couples had sex 77,000 times without condoms. [2, 3]<\/p>\n

This article includes the evidence for U=U: that undetectable viral load makes HIV untransmittable<\/a>.
\nhttps:\/\/i-base.info\/htb\/32308<\/a><\/p>\n

Figure 2 – Viral load levels as HIV infection progresses<\/strong><\/p>\n

\"\"<\/p>\n

Figure 3 – The relationship between viral load and HIV transmission in Rakai Study [4]<\/strong><\/p>\n

\"Fig<\/p>\n

NOTE: Person years is used when calculating risks. It allows for all the time that different people contribute to a study, even when this might be years for one person and only months for another.<\/p>\n

References<\/p>\n

    \n
  1. Rodger AJ et al for the PARTNER study group. Sexual activity without condoms and risk of HIV transmission in serodifferent couples when the HIV-positive partner is using suppressive antiretroviral therapy. JAMA, 2016: 316(2):1-11. (Free online).
    \n    http:\/\/jama.jamanetwork.com\/article.aspx?articleid=2533066<\/a><\/li>\n
  2. Rodger AJ et al. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study. Lancet 2019; published online May 2. (Open access).\u00a0DOI: 10.1016\/S0140-6736(19)30418-0
    \n    https:\/\/www.thelancet.com\/journals\/lancet\/article\/PIIS0140-6736(19)30418-0\/fulltext<\/a><\/li>\n
  3. Zero HIV transmissions in PARTNER study after gay couples had sex 77,000 times without condoms \u2013 an undetectable viral load stops HIV. HTB July 2018.
    \n    https:\/\/i-base.info\/htb\/34604<\/a><\/li>\n
  4. Quinn TC and others. Viral load and heterosexual transmission of HIV type 1. Rakai Project Study Group. New England Journal of Medicine 2000; 342: 921-929.
    \n    http:\/\/www.nejm.org\/doi\/full\/10.1056\/NEJM200003303421303<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    Viral load is the most important factor in the risk of HIV. U=U means that HIV cannot be transmitted if viral load is undetectable. So viral load is more important than condom use. Viral load determines how infectious bodily fluids …<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":5467,"menu_order":9,"comment_status":"closed","ping_status":"closed","template":"page-guides.php","meta":{"footnotes":""},"class_list":["post-5997","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/5997","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/comments?post=5997"}],"version-history":[{"count":1,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/5997\/revisions"}],"predecessor-version":[{"id":17326,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/5997\/revisions\/17326"}],"up":[{"embeddable":true,"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/pages\/5467"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/guides\/wp-json\/wp\/v2\/media?parent=5997"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}