Medical personnel caring for HIV-infected patients may be at risk for acquiring HIV infection through contact with HIV-infected blood and bloody fluids. This is referred as ‘occupational exposure’ to HIV.

The designated doctor or other practitioner should first assess if the exposure reported by the health care worker was significant – that is, with the potential to transmit HIV. There are three types of exposure in health care settings associated with significant risk. These are:
  • Percutaneous injury (from needles, instruments, bone fragments, significant bites which break the skin, etc);
  • Exposure of broken skin (abrasions, cuts, eczema etc);
  • Exposure of mucous membranes including the eye.
[Note – the history and examination may highlight the need to institute other prophylactic and investigative regimens e.g. antibiotic therapy, hepatitis B immunization.

Health Care Workers (HCW) are not at an extremely high degree of risk of acquiring HIV through occupational exposure. The risk varies depending upon the type of exposure.

Type of exposureRisk
Percutaneous 0.3%.
Mucous membrane 0.09%.

Various factors increase the risk of acquiring HIV infection. These include:

  • The depth of the injury
  • Whether the device was visibly contaminated with blood
  • Whether the procedure involved placing a needle directly in an artery or vein
  • Whether the needle was a hollow bore or solid needle
  • Size of the needle
  • Patients viral load
  • Amount of blood or infectious fluid involved in the exposure
  • Duration of the exposure

Blood and bloody fluids are considered infectious. Other potentially infectious materials include semen, vaginal secretions, CSF, pleural, peritoneal, pericardial, amniotic fluids or tissue. Exposure to saliva, tears, sweat, non-bloody urine or faeces is not believed to pose a risk.

Post-exposure prophylaxis (PEP) refers to the treatment of occupational exposures using antiretroviral therapy. The rational is that antiretroviral treatment, which is started immediately after exposure to HIV may prevent HIV infection.

The current guidelines state that:

  • Therapy should be recommended after exposure
  • Therapy should be initiated 1 to 2 hrs of exposure for a period of 4 weeks
  • Recommended 2- and 3-drug regimens are based on the level of risk for HIV transmission based on the exposure type
  • If the source patients HIV status is unknown at the time of exposure, PEP is decided on a case-to-case basis after considering the type of exposure
  • Follow-up counseling and HIV testing should be carried out periodically for at least 6 months (i.e. at baseline, 6 weeks, 12 weeks and 6 months)

Basically, there are two types of regimens for PEP — the Basic and the Expanded regimens. Basic regimen is recommended for mucocutaneous exposures and less severe percutaneous exposures. Expanded regimen is for percutaneous exposure that is more severe. Both the regimens are recommended for a period of 28 days.

RegimenDrugsDosage
Basic Lazid or Synvir1 tab b.i.d.
ExpandedAs above plusIndinavir or Nelfinavir or Efavirenz 800 mg 8 hourly or 750 mg t.i.d. or 600 mg at night

A case-control study conducted by the US Centers for Disease Control (CDC) concluded that the administration of zidovudine prophylaxis to health care workers occupationally exposed to HIV was associated with an 80% reduction in the risk for occupationally acquired HIV infection. Although the efficacy of combination regimens for PEP is unknown, combination drug regimens are currently recommended for PEP.

Side effects of the NRTIs (e.g. zidovudine and lamivudine) have been mainly gastrointestinal (e.g. nausea, vomiting). Malaise, fatigue and headache have also been reported. Some experts consider that stavudine may be substituted for zidovudine as a means of reducing adverse effects, and others consider that zidovudine should not be omitted from any PEP regimen. Efavirenz is associated with neurological side effects but has a lower incidence and severity of rash. Nelfinavir frequently causes diarrhoea. It may accelerate the clearance of certain drugs including oral contraceptives, resulting in reduced contraceptive efficacy. Protease inhibitors have been associated with new onset, and exacerbation, of existing diabetes mellitus.

The exposed HCW should be advised on the following:

  • To abstain from sex
  • Use of condoms to prevent sexual transmission and pregnancy
  • Not to donate blood, plasma, organs, tissue or semen
  • HIV and some other drugs used in therapy can pass through breast milk. Discontinuing breast-feeding should be considered, particularly after high-risk exposures

Adapted from: HIV POST-EXPOSURE PROPHYLAXIS, Guidance from the UK Chief Medical Officers’ Expert Advisory Group on AIDS, February 2004