Write a short note on post-exposure prophylaxis for HIV.

Definition

Post-exposure prophylaxis is the short-term administration of antiretroviral drugs after a potential exposure to HIV, to reduce the risk of establishing infection. Its rationale is that HIV requires 24–72 hours to establish systemic infection after mucosal or parenteral exposure, providing a window in which drugs can prevent seroconversion.

Risk of Transmission Per Exposure

Factors increasing risk: deep injury, visibly bloodstained device, hollow-bore needle (which retains more blood than a suture needle), a device previously in the source's artery or vein, high source viral load (untreated or acute infection), and a large volume of blood.

Indications

• Occupational: needlestick or sharps injury, mucous membrane or non-intact skin exposure to blood or high-risk body fluid in healthcare workers, laboratory staff and waste handlers.
• Non-occupational: sexual assault, unprotected intercourse with a person of known or high-risk HIV status, condom failure, sharing of injecting equipment, and needlestick injury in the community.

High-risk fluids: blood, semen, vaginal and cervical secretions, breast milk, CSF, synovial, pleural, pericardial, peritoneal and amniotic fluid, and any fluid visibly contaminated with blood.

Low or no risk: urine, faeces, saliva, sweat, tears, vomit and nasal secretions — unless visibly bloodstained.

Immediate Management of the Exposure

1. First aid — immediately:

• Wash the wound with soap and running water; allow it to bleed freely. Do NOT squeeze, scrub, or apply caustic agents, antiseptics such as bleach, or attempt to suck the wound — these damage tissue and may increase uptake.
• Irrigate mucous membranes and eyes copiously with water or saline (remove contact lenses first, then irrigate).

2. Report immediately to the designated officer or casualty; do not delay to complete paperwork.

3. Assess the exposure — the type of injury, the device, the fluid, and the depth.

4. Test the source where possible, with consent and counselling — a negative source test allows PEP to be stopped.

5. Baseline testing of the exposed person: HIV, hepatitis B surface antigen and antibody status, hepatitis C, and a pregnancy test where relevant.

Pep Regimen and Timing

• Start as soon as possible — ideally within 2 hours, and certainly within 72 hours. Efficacy falls sharply with delay, and PEP is not recommended beyond 72 hours.
• Do not wait for source testing to start the first dose — begin, and stop later if the source proves negative.
• Duration: 28 days of a three-drug regimen, using the same well-tolerated combinations as first-line treatment (a tenofovir/lamivudine backbone with an integrase inhibitor such as dolutegravir).
• Counselling on adherence, side effects (nausea, fatigue, headache — common and a frequent cause of discontinuation), and safe practices during the follow-up period.

Follow-up

• HIV testing at baseline, 6 weeks, 3 months and 6 months (schedules vary; fourth-generation assays allow shorter follow-up).
• Monitor for drug toxicity — CBC, renal and liver function during the course.
• Advise on preventing secondary transmission for at least 3 months — use condoms, avoid donating blood, semen or organs, and avoid breastfeeding where an alternative is safe.
• Hepatitis B prophylaxis — vaccination with or without hepatitis B immunoglobulin depending on the exposed person's immune status; hepatitis C requires no prophylaxis but does require follow-up testing, with early treatment if seroconversion occurs.
• Psychological support — the anxiety following an exposure is considerable and often under-addressed, particularly after sexual assault; provide counselling and, where relevant, emergency contraception, STI prophylaxis and medico-legal support.

Prevention of Exposure — the Real Solution

Universal (standard) precautions applied to every patient regardless of known status: gloves and protective equipment, safe handling and disposal of sharps in puncture-proof containers, NEVER recapping needles, use of safety-engineered devices, hand hygiene, safe waste segregation, and hepatitis B vaccination of all healthcare workers.