General Principles:

A. What constitutes an exposure?

1.     Exposures known to pose a risk of transmission for bloodborne pathogens:

• Percutaneous injury (hollow needle> solid sharp)
• Splash on mucous membrane
• Splash on non-intact skin

NOTE: The risk of transmission increases with larger volumes of fluid and more severe injuries.

2.     Body fluids known to be infectious:

• Blood
• Any fluid visibly contaminated with blood
• Semen
• Vaginal secretions
• Breast milk

3.     Body fluids presumed to be infectious:

• CSF
• Pleural fluid
• Pericardial fluid
• Peritoneal fluid
• Amniotic fluid
• Joint fluid

4.     Body fluids known NOT to be infectious (if not visibly bloody):

• Tears
• Saliva
• Urine
• Feces
• Sweat
• Emesis

B. What are the initial steps in exposure management?

1. No matter what the health care worker has been exposed to, IMMEDIATE cleaning of the exposure site should also be the 1^st priority.
2. Skin wounds should be cleaned with soap and water - there is no evidence that antiseptics are better than soap and caustic agents (bleach) may do more harm than good.
3. Mucous membranes should be flushed thoroughly with water
4. Eyes should be irrigated with a liter of normal saline.
5. The health care worker (HCW) should be given a tetanus shot if one has not been given in the last 10 years.
6. Even if the exposure poses no risk of Hepatitis B infection it is a good opportunity to make sure the exposed HCW has completed the Hep B vaccine series.

Management of exposures to specific pathogens

Hepatitis C 

Risk of conversion

• Risk of seroconversion following needlsticks involving Hep C positive patients is 3-6%
• Transmission via a mucous membrane exposure has been described in one case 

Post exposure recommendations

• The site should be cleaned immediately
• No medications are indicated
• Immune globulin and alpha interferon are not recommended 

Post exposure follow up

• Average interval between exposure and seroconversion is 8-10 weeks
• EIA is falsely positive in up to 30% of health care workers and falsely negative in 5%
• RNA testing (PCR) may catch infections earlier but detection is highly variable
• Health care workers should have baseline and follow-up EIA tests with PCR confirmation of positive results
• Liver enzymes should also be monitored at regular intervals
• The CDC does not recommend changes in breast feeding or sexual practices in HCW who have suffered a Hep C exposure.

Hepatitis B 

Risk of conversion

• The most infectious of all bloodborne pathogens but represents almost no risk to health care workers who have been successfully vaccinated.
• Risk of transmission is up to 30-40% for susceptible persons exposed to patients who are "e" antigen positive
• Risk of transmission from mucous membrane exposures is less well defined but also felt to be quite high

Post exposure recommendations

• The site should be cleaned immediately
• Further recommendations depend on both the vaccine status of the exposed health care worker and the Hep B status of the patient
• Following an exposure, the HCW should be tested for sAb.  If the sAb titer in the HCW is >10 IU/L then the HCW is considered protected from Hep B. 

1.     HCW never vaccinated

• HCW should receive vaccine ASAP and absolutely within 7 days of exposure
  
• If: the source is Hep B surface antigen positive (HBsAg) OR unknown but felt to be high risk

Then: the HCW should also receive hepatitis B immune globulin (HBIG) .06ml/kg ASAP and absolutely within 7 days of exposure

• If: the source is HBsAg negative OR unknown but known to be low risk

Then: HCW should receive vaccine alone

2.     HCW vaccinated (one or more doses)

• If: the HCW has, or has ever had, adequate anitbody (.10 IU/l) (Ab).
  
  Then: no additional treatment
  
• If: HCW has inadequate Ab AND the source is HBsAg negative OR low risk
  
  Then: HCW should receive a booster dose of vaccine
  
• If: HCW has inadequate Ab AND the source is HBsAg positive OR high risk
  
  Then: HCW should receive HBIG AND and a booster dose of vaccine

 Post exposure follow up

• Hepatitis B sAg is the diagnostic test of choice
• HBsAg should appear within 6 weeks of exposure
• Liver enzymes should be monitored regularly
• The CDC does not recommend changes in breast feeding or sexual practices for HCW who have suffered and occupational exposure to Hep B. 

HIV 

Risk of conversion

• Risk of transmission from percutaneous exposures involving HIV positive patients is estimated at 0.3%
• Risk from a mucous membrane exposure is estimated at 0.1% 

Post exposure recommendations - Overview

• If post exposure prophylaxis (PEP) is to be given they should be given within 2 hours of the exposure to have optimal effect
• AZT is the only drug that has been studied
• CDC recommends adding 3TC to AZT because it is non-toxic and may slow the development of AZT resistant virus
• Protease inhibitors (PIs) are recommended only for more serious exposures or when there has been a delay in treatment
•  Nelfinavir and Indinavir are the recommended PIs
• Exposures involving patients with resistant virus are becoming increasingly common
• If possible, PEP is modified to account for the source patient's retro-viral experience and should include two drugs the patient has never taken
• Rapid HIV tests (SUDS) can be helpful in post exposure counseling
• The rapid test is an EIA that is >99.9% sensitive
• HIV RNA testing may be indicated when source is thought to be in the "window" period (e.g. acute conversion)

 Post exposure recommendations - Specifics

• The site should be cleaned immediately
• Determine the extent of the exposure or "Exposure code"
• Determine the HIV status or risks of the source or "Source code" 

Exposure codes (EC)

1. Exposure to non-infectious fluids:
   
   EC=0
   
2. Exposure involving mucous membrane, non-intact skin or prolonged contact with intact skin:
   
   Small volume EC=1
   Large volume EC=2
   
3. Percutaneous injury:
   
   Less severe (solid needle, minor wound) EC=2
   More severe (hollow needle, major wound, bloody device) EC=3 

Exposure Codes

1. Source patient known HIV negative: SC=0
2. Source patient HIV positive with low viral load: SC=1
3. Source patient HIV positive with high viral load: SC=2  

PEP Recommendations