HIV & post-exposure prophylaxis

This information is written specifically for 4th year medical students on electives overseas, regarding HIV risk and post-exposure prophylaxis

Prevention

• The most effective approach is not to put yourself at risk at all
  
• Use good infection control procedures at all times
  
• Wear gloves if you are likely to be contaminated with body fluids (take gloves with you)
  
• Think about what you will do in the event of an injury before it happens
  

Prevalence
According to the World Health Organisation, the numbers of adults and children estimated to be living with HIV at the end of 2005: 40 million

Epidemiology of HIV world-wide - local seroprevalence

• Highest in sub Saharan Africa
  
• Very high in Central, East, South East and South Africa - up to 20% of the population are HIV infected (Botswana 36%)
  
• Far East - Thailand (2%) and Cambodia(4%), Caribbean (1-5%).
  
• Increasing in India, Eastern Europe and Russia

Risk after exposure

• Risk of acquiring HIV infection following occupational exposure to HIV infected blood is low
  
• Average risk for HIV transmission after percutaneous exposure to HIV infected blood in health care settings is approx 1 per 300
  
• After mucocutaneous exposure, <1 in 1,000
  
• No risk of transmission where intact skin is exposed to HIV infected blood

Calculating HIV seroconversion risk after needlestick/sharps injury

• Known HIV positive - risk is 1 in 300
  
• HIV serostatus unknown, where prevalence of HIV in local/hospital population is 1 in 3 (i.e. 30%) - risk is 300 x 3 = 1 in 900
  
• HIV serostatus unknown, where prevalence of HIV in local/hospital population is 1 in 10 (i.e. 10%) - risk is 300 x10 = 1 in 3,000
  
• HIV serostatus unknown, where prevalence of HIV in local/hospital population is 1 in 100 (i.e. 1%) - risk is 300 x 100 = 1 in 30,000

Occupational exposure
Four factors associated with an increased risk of occupationally acquired HIV infection:

• Deep injury
  
• Visible blood on the device which caused the injury
  
• Injury with a needle from artery or vein
  
• Terminal HIV illness in source patient

Almost all reported cases of HIV seroconversion have occurred after injuries with hollow bore needles

Body fluids and materials which may pose a risk of HIV transmission

• Amniotic fluid
  
• Cerebrospinal fluid
  
• Human breast milk
  
• Pericardial fluid
  
• Peritoneal fluid
  
• Pleural fluid
  
• Saliva in association with dentistry
  
• Synovial fluid
  
• Unfixed human tissues and organs
  
• Vaginal secretions
  
• Semen
  
• Any other fluid if visibly bloodstained
  
• Fluid from burns or skin lesions
  

Post-exposure immediate action

• Wound or non-intact skin to be washed liberally with soap and water without scrubbing
  
• Antiseptics should not be used as no evidence of efficacy and effect on local defences unknown
  
• Free bleeding encouraged
  
• Exposed mucous membranes irrigated with water and remove contact lenses
  

Risk assessment of occupational exposure
Ideally this should not be done by the injured Health care Worker. Assessment of the injury involves:

• Nature of the injury - was there significant contamination?
  
• The risk the patient has HIV (do they have Hep C, Hep B)
  
• Known HIV positive
  
• Person of unknown HIV serostatus
  

Risk assessment of circumstances of exposure
Assess if exposure was significant

• Percutaneous injury (needles, instruments, bites which break skin)
  
• Exposure of broken skin (abrasions, cuts)
  
• Exposure of mucous membranes (including the eye and mouth)
  

Risk assessment of the source patient
If of unknown HIV serostatus a designated doctor should approach the source patient and ask for informed agreement to HIV testing (this should not be the exposed worker)

Current guidelines for UK Health care workers seconded overseas - HIV post-exposure prophylaxis
Guidance from the UK Chief Medical Officers’ Expert Advisory Group on AIDS, UK Department of Health, February 2004 (currently under revision) http://www.dh.gov.uk/assetRoot/04/08/36/40/04083640.pdf

Post-exposure prophylaxis
PEP should ideally be started within 1 hour of the injury. Current EAGA recommendations for UK Health care workers seconded overseas:

• In areas where no anti-HIV treatment is available for patients: 2 drug combination (Zidovudine 250mg and Lamivudine 150mg bd (Combivir 1 tablet BD) for 28 days). BUT anti-HIV treatment is being rolled out to the local population in many developing countries (parts of Uganda, Malawi, Botswana etc). In these areas anti-HIV treatments are likely to be readily available to staff who have significant occupational injuries (ask your supervisor!)
• Where drug resistant HIV likely to be present in local population: 3 drug combination recommended for exposures to ‘treatment experienced’ HIV population (Zidovudine 250mg + Lamivudine 150mg BD (Combivir 1 tablet BD) + Nelfinavir 1250mg BD for 28 days)

Costs
Combivir 1 BD- 7 days = £72.88, 28 days = £291.65 (recommend 7 day pack)
Combivir 1 BD + Nelfinavir 1250mg BD- 7 days = £148.48, 28 days =£896.33 (recommend 7 day pack)

Questions that you need to answer

• Will any work during my elective put me at significant risk of contamination with blood borne viruses? If the answer is no, you do not need to consider PEP
• What is the prevalence of HIV in the local/hospital population? If high, is the local population being treated with anti-HIV treatments?
• What is the local process for handling significant exposures/contamination injuries?
• Are anti-retrovirals locally available within the hospital/health care centre where you are working? If so, which ones, how quickly can they be accessed and cost?
• Who will manage/advise you in the event of a contamination injury? Contact your local supervisor (although you often don’t get a response!)
• Consider insurance to cover repatriation in event of significant injury requiring PEP

Sources of local information about PEP and prescriptions

• Undergraduate office
  
• Department of Genitourinary Medicine Leeds General Infirmary (or ID department St James Hospital)
• Private Prescriptions available late May/early June from GUM (Genito Urinary Medicine)
• Advice on PEP available from GUM Consultant/SpR 24/7 (Office hours 0113 3926762, out of hours LGI switchboard 0113 2432799)
• Follow up advice/drugs/blood tests in the event of an injury from Leeds Student Medical Practice
  

Source: Dr Eric Monteiro, Clinical Director, Department of Genitourinary Medicine
Image source: With permission SOS Children's Villages - the world's largest orphan charity

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Last revision: April 2011