Oral transmission of HIV, reality or fiction? An update

Abstract

Human immunodeficiency virus (HIV) and many other viruses can be isolated in blood and body fluids, including saliva, and can be transmitted by genital-genital and especially anal-genital sexual activity. The risk of transmission of HIV via oral sexual practices is very low. Unlike other mucosal areas of the body, the oral cavity appears to be an extremely uncommon transmission route for HIV. We present a review of available evidence on the oral-genital transmission of HIV and analyse the factors that act to protect oral tissues from infection, thereby reducing the risk of HIV transmission by oral sex. Among these factors we highlight the levels of HIV RNA in saliva, presence of fewer CD4+ target cells, presence of IgA antibodies in saliva, presence of other infections in the oral cavity and the endogenous salivary antiviral factors lysozyme, defensins, thrombospondin and secretory leucocyte protease inhibitor (SLPI).

2016 United Kingdom national guideline on the sexual health care of men who have sex with men

“…(410) and longitudinal studies support the contention that the risk is significantly lower than that for vaginal or anal sex and may be zero in some untreated individuals (45). There is no published estimate for an upper confidence limit for transmission risk through oral sex with undetectable HIV viral load but given that sexual behaviours in both HPTN 052 and the PARTNER study would include oral sex in both heterosexual and MSM couples, it seems that a best estimate of transmission risk for oral sex with undetectable viral load is zero.…”

Characterization of SIV in the Oral Cavity andin VitroInhibition of SIV by Rhesus Macaque Saliva

“…[11][12][13][14][15] Multiple endogenous inhibitory factors have been identified in saliva, which contribute to this antiviral effect, including mucins, cystatins, defensins, secretory leukocyte protease inhibitor, lactoferrin, anti-HIV antibodies, and other factors. 2,10 The innate inhibitory capacity of saliva is, at least in part, responsible for limiting viral expression and transmission of HIV in the oral cavity. 2,3,16 Simian immunodeficiency virus (SIV)-infected rhesus macaques are a widely accepted model for the study of HIV transmission and pathogenesis.…”

“…2,10 The innate inhibitory capacity of saliva is, at least in part, responsible for limiting viral expression and transmission of HIV in the oral cavity. 2,3,16 Simian immunodeficiency virus (SIV)-infected rhesus macaques are a widely accepted model for the study of HIV transmission and pathogenesis. Experimental infection of macaques with SIV leads to immune dysfunction and progression through advanced disease similar to HIV infection in humans.…”

“…1 Epidemiologic and clinical reports agree that transmission of virus rarely occurs via an oral route in adults, despite the presence of detectable levels of virus in the saliva, salivary glands, and oropharyngeal tissues of HIV-infected patients. [2][3][4] The level and potential infectivity of virus present in the oral cavity of HIV-positive individuals have been evaluated using various methodologies. 2,5 Studies using culture-based methods have reported low frequencies of HIV-1 detection in saliva, while more quantitative methods, such as polymerase chain reaction (PCR), have led to higher frequencies of detection.…”

“…[2][3][4] The level and potential infectivity of virus present in the oral cavity of HIV-positive individuals have been evaluated using various methodologies. 2,5 Studies using culture-based methods have reported low frequencies of HIV-1 detection in saliva, while more quantitative methods, such as polymerase chain reaction (PCR), have led to higher frequencies of detection. 5 One study detected HIV-1 RNA by PCR in 96% of cell-free whole saliva samples, with a median viral load of 162 copies/ml saliva (range 0-72,080 copies/ml).…”