Post-exposure prophylaxis for HIV
From IDWiki
Background
- Can be sexual or non-sexual; consensual or non-consensual; and heterosexual or homosexual
- HIV does not survive very long outside of the human body, which is why a random needle in park, for example, is very low risk
Management
Risk Assessment
- If the source person is available and consents to testing, this can be done to more accurately risk stratify the exposure
- In general, prophylaxis is indicated if the estimated risk is greater than 0.1%
| Risk | Examples |
|---|---|
| substantial | HIV-positive with detectable viral load |
| HIV status unknown, but from a population with high prevalence such as MSM or PWID | |
| low but nonzero | HIV positive and believed to have undetectable viral load, with concomitant STI at time of exposure |
| negligible or none | confirmed HIV negative |
| HIV positive with confirmed viral load <40 copies/mL without known STI at time of exposure | |
| HIV status unknown, in the general population |
| Population | Risk |
|---|---|
| General population | 0.25% |
| Men who have sex with men | 23% |
| Person who injects drugs |
| Risk | Exposure | Estimated risk per act % |
|---|---|---|
| Very high | Transfusion | 92.5 |
| High | Anal (receptive) | 1.38 |
| Needle sharing | 0.63 | |
| Moderate | Anal (insertive) | 0.11 |
| Vaginal (receptive) | 0.08 | |
| Vaginal (insertive) | 0.04 | |
| Low | Oral sex (giving) | — |
| Oral sex (receiving) | — | |
| Oral-anal contact | — | |
| Sharing sex toys | — | |
| Blood on compromised skin | — |
| Risk of HIV-Positive Source | Risk From Exposure | Action |
|---|---|---|
| substantial | low | PEP not required |
| moderate or high | initiate PEP | |
| low | low | PEP not required |
| moderate or high | consider PEP | |
| negligible or none | low | PEP not required |
| moderate or high | PEP not required |
Antiretroviral Therapy
- Screen for sexual assault, counsel about safe sex
- Screen for pregnancy and get baseline investigations (below)
- Start antiretroviral therapy within 72 hours and continue for 28 days
- First-line: tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg PO daily plus raltegravir 400 PO bid
- Alternative: tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg PO daily plus dolutegravir 50 mg PO daily
- Alternative: tenofovir disoproxil fumarate/emtricitabine 300 mg/200 mg PO daily plus darunavir/ritonavir 800 mg/100 mg PO daily
- Don't forget screening for hepatitis A, hepatitis B, hepatitis C, gonorrhea, chlamydia, and syphilis
Investigations
| Investigation | Baseline | Week 12 | Notes |
|---|---|---|---|
| CBC | X | ||
| ALT | X | repeat at 2 weeks if abnormal | |
| creatinine | X | repeat at 2 weeks if abnormal | |
| hepatitis A serology | X | ||
| hepatitis B serology | X | includes HBsAb, HBsAg, and HBcAb | |
| pregnancy test | X | ||
| HIV serology | X | X | repeat at 6 months if hepatitis C seroconversion |
| hepatitis C serology | X | X | |
| gonorrhea and chlamydia | X | X | urine, throat, and rectum, depending on reported sexual activity |
| syphilis serology | X | X |
Follow-Up
- Initial visit; follow-up at 4-6 weeks; then repeat bloodwork at 12 weeks to 4 months
- Take advantage of the opportunity to counsel patients on STIs, substance use, etc.
Further Reading
- Canadian guideline on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis. CMAJ. 2017;189(47):e1448-e1458. doi: 10.1503/cmaj.170494
