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Can we prevent infection after an exposure? The world of post-exposure

prophylaxis (PEP)

James WiltonProject CoordinatorBiomedical Science of HIV Prevention jwilton@catie.ca

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HIV/AIDS in Canada

• Number of people living with HIV• 57,000 in 2005• 65,000 in 2008

• 2,200 to 4,200 infected in 2005• 2,300 to 4,300 infected in 2008

• MSM (44%)• People who use injection drugs (17%)• Women (26%)• Aboriginal (12.5%)

Source: Public Health Agency of Canada

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Improving HIV prevention

1. Do better with the strategies that we already have

2. Develop new biomedical technologies to prevent HIV

3. Adopt a more comprehensive approach to HIV/AIDS prevention

What is post-exposure prophylaxis (PEP)?

• Post After

• Exposure When a fluid containing HIV comes into contact with mucous membranes or non-intact skin

• Prophylaxis An action taken to prevent infection or disease

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What is PEP to prevent HIV infection?

• The use of a combination of antiretrovirals by HIV-negative individuals for a short period of time after a suspected or known exposure to HIV

• Must be started as soon as possible but within 48-72 hours after the exposure

• Must be taken everyday for 28 days• Must avoid additional exposures while taking

PEP

• Types of exposures• Occupational• Non-occupational

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Occupational vs. non-occupational exposures

Occupational• Work-related exposures to HIV• Needle-stick injuries• Sharp objects

• “Standard of care”

Non-occupational (nPEP)• Exposures outside of the workplace• Non-consensual sex• Consensual sex• Needle sharing

• Not “standard of care”

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Does PEP work?

• No randomized controlled studies

• Observational studies• Studies with control groups• Evaluations of PEP programs

• Indirect evidence• Non-human primate (monkey) studies • Prevention of mother-to-child transmission

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How does PEP work?

• Infection does not occur instantly after an exposure to HIV• The virus needs to spread

throughout the body • This may take up to 3 days after the

exposure

• The “window of opportunity” for PEP• The brief period of time - after an

exposure - where infection has not yet occurred

• During this time, PEP may be able to stop HIV from causing an infection

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How well does PEP work?

• We don’t know how protective PEP is

• We know it is not 100% protective• People have become infected despite using PEP

• Protection likely depends on: • Starting PEP quickly• Being adherent• The risk of transmission from the exposure • Avoiding additional exposures• The number and type of antiretrovirals used

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Does occupational PEP work?

• Study details• 712 healthcare workers exposed to HIV-infected

blood

• Study findings• 256 did use PEP

– 9 became infected • 456 did not use PEP

– 24 became infected

PEP reduced the risk of HIV transmission by 81%

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Does non-occupational PEP work?

• Study details• 200 gay men in Brazil given a 4-day starter-pack of

PEP• Followed for over 2 years

• Study findings• 68 men did use PEP after a high risk exposure

– 1 became infected• 86 men did not use PEP after a high risk exposure

– 10 became infected

Study did not calculate effectiveness of nPEP

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Failure of nPEP to prevent infection is rare

It is difficult to interpret how protective PEP is… • Would people have remained uninfected

without using PEP?• Among those who became infected, was

PEP used correctly?

# People who used nPEP # HIV infections

Amsterdam 261 5France 776 1Denmark 374 1Australia 1552 0Switzerland 710 0San Francisco

702 6

Montreal ~900 6

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What’s involved in taking PEP?

1. Assessment

2. Counseling

3. Prescription

4. Follow-up

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What’s involved in taking PEP?

1. Assessment• Was the exposure within the last 72 hours?• Is the exposed person HIV-negative? • Was the exposure high-risk?

• What activity led to the exposure?• What was the HIV status of the source person?

2. Counseling

3. Prescription

4. Follow-up

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Guidelines for non-occupational PEP

• When is PEP recommended?

• Example, the CDC nPEP guidelines

• Is there a substantial risk from the activity?

– No PEP not recommended

• If yes, was the exposure to someone who was HIV-positive?

– No PEP not recommended– Unknown Case-by-case basis– Yes PEP recommended

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What’s involved in taking PEP?

1. Assessment

2. Counseling• What are the risks and benefits of starting

PEP?• Is the exposed person ready to start PEP?• Adherence and risk-reduction counseling

3. Prescription

4. Follow-up

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What’s involved in taking PEP?

1. Assessment

2. Counseling

3. Prescription• What antiretrovirals? How many?• Starter-packs

4. Follow-up

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Guidelines for non-occupational PEP

USA Australia WHO UK EuropeTiming of PEP Within 72 hours Within 48

hours

Number of antiretrovirals

2 or 3 3

What antiretrovirals?

Two NRTIsTwo NRTIs + PI/NNRTITwo NRTIs + tenofovir

Two NRTIsTwo NRTIs + PI

Truvada + Kaletra

Duration 28 daysBarber and Benn 2010

NRTI = nucleoside reverse transcriptase inhibitorNNRTI = non-nucleoside reverse transcriptase inhibitorPI = protease inhibitorTruvada = tenofovir + emtricitabineKaletra = Lopinavir

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What’s involved in taking PEP?

1. Assessment

2. Counseling

3. Prescription

4. Follow-up • Ongoing risk-reduction and adherence

counseling • Monitoring/management of side-effects and

toxicity• HIV testing

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Why do so few people use nPEP in Canada?

• People may not think they are at risk

• Lack of national and provincial guidelines

• Use of nPEP is not promoted

• Only available in some emergency departments and urgent care clinics

• Cost is only covered by some provincial and private insurance plans

• Side-effects, adherence, monitoring, counseling

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Why is there reluctance to make nPEP more widely available?

• Feasibility

• Cost-effectiveness

• Risk compensation

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Why is there reluctance to make nPEP more widely available?

• Feasibility• Research suggests that nPEP programs are feasible

but challenges exists

• Cost-effectiveness• Research suggests that targeted nPEP programs are

cost-effective

• Risk compensation• Research shows that there is little evidence of risk

compensation

Enhancing the potential benefit of PEP• Access to PEP provides an opportunity to offer

additional services to people at high risk of infection

• Research study• Study details

– In addition to PEP, participants received either:1. Standard risk-reduction counseling (2-sessions)2. Enhanced risk-reduction counseling (5-sessions)

– Participants followed for a year after initiating PEP

• Study findings– Standard counseling 12.3% became infected– Enhanced counseling 2.4% became infected

• Combining PEP with enhanced risk-reduction counseling can make it a more effective prevention tool

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A comprehensive approach to PEP

• Integration into a comprehensive prevention program

• Targeted outreach and educational campaigns

• Prevention, care and support services• Adherence counseling and support• Risk-reduction counseling • Psychological counseling and trauma support• Mental health and addiction services

• Advocacy to improve access

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Clinique l’Actuel: 9 years experience with nPEP• Sexual health clinic in Montreal, Quebec

• Over 1,139 consultations• Prescribed to over 900 people• Majority of PEP users are gay men• 80% first time using PEP• Average time to consultation after exposure - 29 hours

• Challenges• 68% complained of side-effects• 50% completed follow-up

• 6 HIV infections• Many reported ongoing exposures

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CATIE’s Programming Connection

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CATIE Resources: PEP factsheet and article

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Thank you!