Chapter 55, ‘HIV: management’, pp. 621–651). With effective ART, consistently undetectable viral load, and the absence of genital ulcer disease or concurrent STI, the risk of onward transmission is negligible.HIV prevention is multifaceted and requires input from a range of disciplines.
Public health campaigns, and education in schools and high risk groups to increase awareness, condom use, and safe sex. Education and support around chemsex and binge drinking may also reduce high-risk sexual behaviour. Reducing STIs and improving genital health also has some role to play in reducing HIV transmission. Circumcision has also been associated with reduced risk of HIV acquisition.
Amongst some groups of MSM, sexual practices to reduce transmission are sometimes used, such as ‘sero-sorting’, where those with HIV infection choose partners who also have HIV infection and vice versa. ‘Sero-positioning’ is where the HIV –ve partner will choose a sexual position associated with lower risk of transmission. The effectiveness of these strategies is unproven, so cannot be recommended.
The ‘90 90 90’ WHO target for HIV, aims to have 90% diagnosed, 90% on treatment, and 90% undetectable by 2020. In the UK, 12% of people with HIV remain undiagnosed. Undiagnosed HIV infection accounts for disproportionate onward transmissions. Campaigns such as HIV testing week, and universal testing in medical admission units and GP surgeries in areas where prevalence in greater than 2/1000, availability of POCT in voluntary sector centres, postal HIV testing kits, as well as raising awareness of HIV indicator diseases, where a HIV test should be considered, will all help reduce undiagnosed HIV.
Guidelines recommend ART for all diagnosed with HIV, regardless of CD4 count, but those who have not started treatment should be offered treatment in the context of a discordant relationship, frequent partner changes or casual partners. This is referred to as TasP (treatment as prevention Chapter 55, ‘HIV: management’, pp. 621–651). With effective ART, consistently undetectable viral load, and the absence of genital ulcer disease or concurrent STI, the risk of onward transmission is negligible.
Universal antenatal HIV testing has been part of routine practice since 2000 and for mothers diagnosed with HIV, medical, obstetric, and post-natal infant management ( Chapter 56, ‘HIV: pregnancy’, pp. 653–658) transmission of HIV from mother to infant has reduced significantly to <1% in the UK.
PEP following an HIV risk has been available for several years, but more recently, PrEP has been shown to be effective for certain high-risk individuals. Both should be considered as part of the HIV prevention tool kit.
PEP and post-exposure prophylaxis after sexual exposure (PEPSE) are the administration of antiretroviral agents after a risk exposure to HIV in order to prevent HIV acquisition. Studies suggest antiretrovirals (ARVs) given <48–72 hours after exposure, reduce dissemination and replication.
Where the risk of acquisition is >1/1000, PEP should be offered and where the risk is between 1/1000 and 1/10,000 PEP should be considered. Transmission varies according to type of exposure, infectivity of the source and host characteristics. PEP is not recommended where the HIV +ve source has viral load (VL) <20 for >6 months on effective therapy (
www.bhiva.org/PEPSE-guidelines.aspx).
Risk of transmission = Risk or source having HIV × exposure risk
Insertive anal sex × UK MSM = 1/90 × 5.9/100 = 5.9/9000 = 1/1525
• Breaches to mucosal barrier: ulceration/trauma/infection.
• Black African ethnicity ♂ 4.1%, ♀ 7.1%
• Receptive anal intercourse 1/90: with1/65 or without 1/170 ejaculation.
• Insertive anal intercourse 1/666: with 1/909 or without 1/161 circumcision.
• Receptive vaginal intercourse 1/1000.
• Insertive vaginal intercourse 1/1219.
• Giving or receiving fellatio <1/10,000.
• Semen splash in eye <1/10,000.
• Unprotected receptive anal sex, where source has VL>200.
• Unprotected insertive anal sex, where source has VL>200.
• Unprotected receptive vaginal sex, where source has VL>200.
• Unprotected receptive anal sex, where source is from high-risk group/country.
• Where risk of transmission is 1/1000–1/10,000 with additional factors that increase transmission, e.g. sexual assault (traumatic sex).
• Try to determine HIV status of source: if occupational exposure, wash wound and gently encourage bleeding. Another HCW should gain consent from source for blood-borne virus screening.
• If known HIV +ve source, try to establish VL.
• Baseline investigations should include HBV sAg, HCV, HIV, U&E, LFT, urinalysis, and if sexual exposure also syphilis, STI screen and pregnancy test.
• Patient should see a HIV specialist at earliest opportunity.
• Consider if PrEP appropriate following completion of PEPSE.
• Tenofovir/emtricitabine od + raltegravir 400 mg bd.
• Started <72 hours after (most recent) exposure.
• If further exposure within 2 days of completion, continue PEP for 48 hours after last exposure risk.
The decision for PEP should be based on risk of HIV acquisition and not to treat anxiety. Referral to health psychology or a HA may be beneficial for anxiety related to HIV transmission.
Estimated UK incidence of HIV has not fallen over the past decade. Undiagnosed prevalence remains high at 12%, with the undiagnosed population thought to account for the majority of new transmissions. PrEP is one of many strategies to reduce new HIV transmissions. It has been shown to be cost-effective in certain high-risk individuals.
risk of HIV acquisition who may benefit from PrEP• MSM, transmen, and transwomen having condomless anal sex.
• Sexual partners of people with detectable HIV viraemia or within 6 months of viral suppression.
• Heterosexual reporting condomless sex with HIV +ve person(s), with ongoing risk.
• Person who has had PEPSE, bacterial STI, or Hep C in past year.
• People may also present already taking PrEP bought online.
For MSM, two regimens have been shown to be effective:
• Event-based TDF/emtricitabine (FTC): 2 tablets 2–24 hours before sex + 1 tablet od for next 48 hours. Most appropriate if having unprotected anal intercourse (UPAI) <1 weekly
• Oral daily TDF/FTC: most appropriate if UPAI >1 weekly, or unable to predict UPAI, or if HBV co-infected.
For heterosexuals, trans men and trans women 1 tablet daily TDF or TDF/FTC.
For anal sex, PrEP is effective after 2–24 hours if initiated with double-dose TDF/FTC; should be continued until 48 hours after last risk.
For vaginal sex PrEP is effective after 7 days of daily PrEP and should be continued for 7 days after the last risk.
Availability varies in the different countries of the UK:
• Scotland and Wales: available in NHS sexual health clinics.
• England: available in some centres as part of PrEP impact trial.
• Also available to buy online.
For further information and where to obtain PrEP go to:
• Timing and type of condomless sex.
• Previous STI/HIV screen, last HIV test.
• Previous medical history (renal/bone disease/Hep B).
• Drug history (prescribed/recreational).
• If already sourced PrEP online check source, consider therapeutic drug monitoring (TDM).
• Importance of adherence to PrEP.
• Risk of HIV infection and resistance with poor adherence.
• 3-monthly STI/HIV screen (annual if stable heterosexual couple).
• Potential side effects, including renal impairment and reduced bone mineral density.
• Risk reduction, including condoms and chemsex support.
• Symptoms of HIV seroconversion illness.
• 4th-generation HIV test +/–POCT HIV.
• STI, hepatitis B and C screen.
• Urinalysis and serum creatinine.
• Information on where to obtain PrEP.
• If POCT –ve can start PrEP same day.
• 3-monthly follow-up or sooner if within window for STI/HIV screen.
• Check and support adherence to PrEP.
• STI/HIV/hepatitis C screen 3-monthly (6–12-monthly if stable heterosexual couple).
• Serum creatinine + eGFR annually, if eGFR >90 and age <40, at least 6-monthly, if eGFR 60–90, age >40 or other risk factors. If eGFR <60, careful risk assessment and renal advice recommended.
Further information
British HIV Association guidelines: http://www.bhiva.org/guidelines.aspx