1. Post-Exposure Prophylaxis
Dr Michael J. Boyle

2. Common presentations Needle in the park
Heterosexual sex - Vaginal Oral
Male to male sex - Anal Oral
Rape - Heterosexual male to male
Needle sharing / needle assault
Other - trauma, dermatitis, broken skin exposure

3. Assessing the risk 1. The exposure - type of sex
- type of injecting equipment
- nature of injury (needle gauge)
- nature and volume of body fluid
- time since exposure
2. The source - Known +ve source VL if known; Stage of HIV
- If status unknown, ? epi risk

4. Management: First Steps
Clean wound (soap and water) No Caustic agents
Flush mucous membranes with saline
Vaginal/rectal douching not recommended
Assess tetanus hepatitis B vaccination status
Organise pre-test counselling
Risk assessment: risk of exposure X Source risk
Factors that may enhance that risk assessment

5. Current HIV seroprevalence in Australia (0.066%)
Type of Exposure
Receptive anal intercourse
Receptive vaginal intercourse
Insertive vaginal or anal
Needle injury
Using contaminated needles
Mucous membrane
HIV Transmission Risk
< 3.0% (1 in 125 to 1 in 30)
< 0.1% (1 in 2000 to 1 in 667)
< 0.1% (1 in 3333 to 1 in 1111)
~ 0.3% (1 in 313)
~ 0.6% (1 in 149)
~ 0.1% (1 in 1111)
Current HIV seroprevalence in Australia (0.066%)
Homosexual men 3-15%
Injecting drug users ~1%
Homosexual male IDU 17%
Heterosexual
STD clinic attendees 0.1%
Blood donor %

6. Exposure Source unknown Source Known Homosexual men Receptive anal
1 in 222
3% =
1 in 33.3
Insertive anal
0.1% x 15% =
1 in 6,666
0.1% =
1 in 1,000
Sharing needles
0.6% x 15% =
1 in 1,111
0.6% =
1 in 167
Non-intact skin
~ 0.6% =
Mucous membrane
~ 0.1% =
Heterosexual
Receptive vaginal
0.1% x 0.1% =
1 in a million
~ 0.1%

7. Epidemiological risk varies

8. Other Risk Factors and Balancing Risk
? Patient viral load, treatment history
? Presence of STI in source or exposed person
? Ulcerative or inflammatory oral disease if oral sex
? Volume of blood if needle exposure
1 in 6 million for death from bee sting per year
1 in 5 million for childhood kidnap per year
1 in 2 million die by lightning strike each year
1 in 800 die due to smoking-related illnesses

9. Management: What needs to be discussed
Pre-test counselling (may be delayed)
Risk carefully explained
HIV pep is NOT a proven therapy
4 week therapy (can be difficult)
Protection for others (condom, needle sharing, breast feeding, blood donation, safe work practices)
Side effects of drugs (don’t confuse seroconversion)
Risks in pregnancy
It is the choice of the patient and can stop anytime
Need for follow-up
Counselling and support ! ! ! ! !

10. Drug therapy Consider:
Unprotected receptive or insertive anal intercourse
Sharing needles and syringes
Unprotected receptive or insertive vaginal sex
Mucous membrane or non-intact skin exposure to HIV-positive blood
Lesser risk, but consider
Unprotected receptive fellatio if source known positive AND recipient
Mucous membrane, non-intact skin exposure to HIV-infected secretions
ALSO, source should be known positive, or at epidemiological high risk
Also, consider whether presents within 72 hours

11. The drugs: which one 2 drugs most commonly: combivir
Factor in drug history of source
ALWAYS consult when prescribing
3 drugs if known Positive source AND advanced disease High viral load Has resistant virus
Never use nevirapine

12. Document For exposed individual
Nature, time of exposure, factors in exposure, time seen
Recent HIV testing, previous exposures, pep use
Current STIs; history of other STIs; Hep B,C history
Pregnant? breast feeding?
Significant medical disease, medication
Discussion around PEP understanding, risk/benefit, treatment decision and what was recommended
Consent for baseline testing after pre-test counseling: HIV, pregnancy, hepatitis B and C, blood count, LFT
For source individual
HIV stage, CD4 count, viral load, retroviral history, resistance tests
hepatitis status, Hepatitis B infectivity, hepatitis C Viral load
STI history: present and past infections

13. Management: what else to consider
Tetanus
Hepatitis B
Hepatitis C
Other STIs
Sepsis (Staphylococcal infection in IDU)

14. Management: Hepatitis B
If ever PROVEN immune to hepatitis B by vaccine or infection, no need for further therapy
If non-immune, commence vaccination +/- HBIg within 72hours.
If previously completed full vaccination >90% protected
sAg positive; eAg, DNA positive: 30-40%
sAg pos; eAg, DNA neg: < 6%

15. Hepatitis C Risks High prevalence in drug users
If sero-positive, risk for needlestick 1.8%
If RNA positive, risk of needlestick 10%
Potential benefit of early treatment during seroconversion
Follow up testing via serology +/- LFT, viral assessment

17. Follow up Post-test counselling 3 months follow up for HIV if no PEP
6 months follow up for HIV if PEP given
6 months follow up for hepatitis B and C
Advice re avoiding future exposures