Occupational Exposures to Bloodborne Pathogens

Occupational Exposures to Bloodborne Pathogens
By:Arjun Srinivasan
Johns Hopkins Hospital

Outline
* What’s an exposure?
* 1st step in all exposures - Clean the site!!
* Specific pathogens
o Hepatitis C
o Hepatitis B
o HIV

Scope of the Problem
Impossible to measure the psychological stress that an exposure places on a health care worker
At Risk Exposures
1. Percutaneous injury
Hollow needle > Solid sharp
Visible blood
Deep injury
Device in patient’s artery or vein
2. Splash on non-intact skin
3. Splash on mucous membrane

Risks From Body Fluids
* Known to be infectious:
o Blood
o Any fluid visibly contaminated with blood
o Semen
o Vaginal secretions
o Concentrated virus (used in labs)
* Potentially infectious
o CSF
o Pleural fluid
o Pericardial fluid
o Peritoneal fluid
o Amniotic fluid
o Synovial fluid
o Tissue samples
* Not Infectious (if not visibly bloody)
o Tears
o Saliva
o Urine
o Feces
o Sweat
o Emesis

The Solution to Pollution . . .
* Exposure site should be cleaned IMMEDIATELY! This may be the most important part of PEP
* Skin wounds should be washed with soap and water
* No evidence that antiseptics are useful and caustic agents (bleach) may do more harm than good
* Mucous membranes should be flushed thoroughly with water
* Eyes should be irrigated with a liter of saline

A word from our lawyers . . .
* ALL exposures should be reported to the proper people (Occupational health, Employee health etc.)
* Disability claims can be denied if follow up reporting was not done right

Hepatitis C
Hepatitis C: Risk of Exposure
Hepatitis C: Risk of Disease
Post Exposure Recommendations
* Clean the site immediately
* Hepatitis B immune globulin has NOT been effective
* Interferon is NOT recommended at this time
Hepatitis C: Follow Up
* Enzyme linked immunoassay (EIA) is screening test of choice
* ALL exposed HCWs should have LFTs monitored
* Average interval between exposure and seroconversion with EIA is 8-10 weeks
* Follow up guidelines vary - CDC recommends follow up at 4-6 months
Hepatitis C: Follow up issues
* EIA is falsely positive in up to 50% of HCW and falsely negative in 5% - results must be confirmed by RIBA or VL
* PCR may catch infection earlier but detection is highly variable
* Immediate referral for treatment if HCW seroconverts
Hepatitis C: Counseling
* Risk of transmission to infants and partners is thought to be low
* Exposed HCW do not need to modify sexual practices, stop breast feeding or refrain from becoming pregnant
* Should not donate blood

Hepatitis B
Hepatitis B: Risk of Exposure
Hepatits B: Outcome of Infection
* In patients who are infected with Hep B:
o 25% get jaundice
o 5% require hospitilization
o 6-10% become chronically infected
o .125% die of fulminant hepatitis

Hepatitis B: Good News
* Most HCWs have been vaccinated and vaccine offers virtually complete protection to responders
Hepatitis B: Bad News
* Some employees are NOT vaccinated
* 6-10% of vaccinees do NOT develop antibody
* Really bad news:
CDC estimates that 50-75 HCW die from Hep B each year
Hepatitis B: Post Exposure
* Clean the site immediately
* Determine the vaccine status of the HCW
* Determine the surface antigen status of the source patient

Hep B: HCW Never Vaccinated
* HCW should receive vaccine ASAP
1. Source patient is sAg positive:
HCW should also receive one dose of Hep B immune globulin (HBIG) .06ml/kg (1 vial=5 ml) ASAP and absolutely within 7 days of exposure
2. Source patient sAg neg or unknown
Vaccine alone
Hep B: HCW Vaccinated (one or more doses)
* Source patient should be tested for sAg AND HCW should be tested for sAb
* If HCW has adequate Ab >10 IU/mL (now or at any time) then no additional treatment
* IF HCW has inadequate Ab:
1. If pt is sAg negative:
HCW should get booster dose of vaccine (or complete series)
2. If pt is sAg positive:
HCW should receive HBIG AND a booster dose of vaccine at different sites (complete series if necessary)
If HCW has inadequate Ab:
3. Unknown source:
Give vaccine booster or complete series
Vaccine non-responders
* If HCW has inadequate Ab after 3 dose series they should get another series: 30-50% chance of responding to 2nd series
* If no response to 2nd series HCW should be considered susceptible
* PEP for known non-responders exposed to Hep B positive or high risk unknown sources: 2 doses of HBIG- 1 at exposure then 4 weeks later
Hep B: Follow Up Testing
* Hepatitis B sAg is the test of choice as it rises in about 6 weeks
* LFTs should be monitored at regular intervals
Post Exposure Counseling
* Risk of transmission to infants and partners is thought to be low
* Exposed HCW do not need to modify sexual practices, stop breast feeding or refrain from becoming pregnant
* Should not donate blood
HIV
HIV: Risk of Exposure
* Risk of transmission from percutaneous expsosures involving HIV positive pts estimated at 0.3%
* Risk from mucous membrane exposure estimated at 0.1%
* As of 2000 there were 56 confirmed and 138 possible cases of occupational transmission in the US
Rationale for PEP
* HIV infects dendritic cells and then regional lymph nodes before becoming systemic
* AZT blocks infectivity of HIV infected dendritic cells
* Goal of PEP is to halt viral replication before systemic infection is established

Does It Work?
* Several animal studies showing efficacy
* Peri-natal prophylaxis has been effective
* Retrospective study showed that risk of seroconversion after exposure was 81% lower in HCWs who took AZT PEP.
Time is Virus
What To Use?
* Before: AZT+3TC +/- IDV or NFV
* Now: Becoming more difficult to answer!
* Regimens may need to be tailored based on the treatment history of the source patient -Surveillance study from 1998-1999 found that 39% of virus from source patients had some NRTI resistance and 10% had some PI resistance.

Nucleoside Reverse Transcriptase Inhibitors (NRTI)
* Still form the backbone of most regimens
* AZT has been formally studied thus it should be included if possible
* Addition of 3TC is recommended because:
1. It appears non-toxic
2. It has some synergistic effect with AZT with respect to mutations
* If source patient’s virus is felt to be resistant to AZT or 3TC alternatives include:
* d4T + 3TC
* d4T + ddI
* Role of abacavir?
* Role of tenofovir?
Protease Inhibitors (PI)
* Are very potent anti-virals and work very well in patients
* BUT they have significant side effects and can cause HCW to stop PEP altogether
* PI should be recommended primarily when the exposure is high risk
* Any PI can be used but indinavir and nelfinavir have been used the most
Non Nucleoside Reverse Transcriptase Inhibitors (NNRTI)
* Not much experience using these for PEP
* Use should be reserved for situations when source patient’s virus is thought to be resistant to all PIs
* Nevirapine should probably be avoided as PEP: from 1997-2000 there were 22 reports of serious toxicity in HCW taking it for PEP

Toxicity of PEP
Side Effects of PEP
PEP Counseling
* Clean the site immediately
* Determine the HIV status of the source
* Determine the extent of the exposure
PEP management: Source Patient Testing
* Crucial 1st step as most exposures do NOT involve HIV positive patients
* Rapid test kit (SUDS) is available and yields an answer in about 30 minutes
* Rapid test is an EIA that is >99.9% sensitive
* Testing of blood on sharps is NOT recommended
* Patient consent is required in Maryland
HIV RNA Testing of Source
* No official recommendations and test is not approved for this indication
* Should be reserved for cases where there is a suspicion of acute retroviral conversion

Source Patient
1. Patient HIV negative - No PEP
2. Patient HIV positive
Low viral load / high CD4 = class 1
High viral load / low CD4 = class 2
3. Patient HIV positive, unknown CD4, VL
Use best judgement - err towards class 2
4. Unknown source
Exposure Types
1. Non-infectious fluids - No PEP
2. Mucous membrane, non-intact skin
Small volume
Large volume
3. Percutaneous injury
Less severe
More severe
HIV PEP Recommendations
Percutaneous injuries
Less severe
* Source pt HIV negative - No PEP
* Source pt class 1 - Recommend 2 drugs
* Source pt class 2 - Recommend 3 drugs
* Source of unknown status- Consider 2 drugs in setting where exposure to HIV positive pt likely or if pt has HIV risk factors

HIV PEP
More severe injury
* Source pt HIV negative - No PEP
* Source pt HIV class 1 or 2 - Recommend expanded 3-drug regimen
* Source of unknown status - Consider 2 drugs in setting where exposure to HIV positive pt likely or if pt has HIV risk factors
HIV PEP
Mucous membrane exposures
Small Volume
* Source pt HIV negative - No PEP
* Source pt class 1 - Consider 2 drugs
* Source pt class 2 - Recommend 2 drugs
* Source of unknown status- Consider 2 drugs in setting where exposure to HIV positive pt likely or if pt has HIV risk factors
Large volume
* Source pt HIV negative - No PEP
* Source pt class 1 - Recommend 2 drugs
* Source pt class 2 - Recommend 3 drugs
* Source of unknown status- Consider 2 drugs in setting where exposure to HIV positive pt likely or if pt has HIV risk factors
Duration of Treatment
* Current recommendation is 4 weeks but this is an arbitrary selection
* Animal studies suggest 10 days is too short but 28 days conferred protection
Resistance
* Becoming a significant problem now that so many patients are getting treated
* Treatment history can be helpful in the acute setting
* Recent history may be more important than remote
Resistance Issues
* Full medical history often not available when the exposure occurs - PEP should NOT be delayed
* Data from maternal transmission studies shows viral resistance does not preclude benefit
* Consultation with someone experienced in HIV treatment is recommended in cases where HIV resistance is possible
* PEP may need to be modified once more history is available
* Resistance testing is too slow to be of use right now

PEP and Pregnancy
* Women of child bearing age should be offered a pregnancy test before starting PEP
* BUT, recommendations on starting PEP should NOT change just because HCW is pregnant

HIV medications to avoid in Pregnant HCW
* d4T, ddI: have been associated with severe lactic acidosis in pregnant women
* Efavirenz: is teratogenic in primates
* Indinavir: causes hyperbilirubinemia in newborns if given near time of delivery

Post Exposure Testing
* Testing should be done at regular intervals (eg 6,12 weeks and 6 months)
* Testing should continue for 12 months if the HCW contracts HCV from the exposure
* Unclear if testing should be prolonged in exposures to pts with HIV and HCV or in HCW who have history of impaired Ab responses
* EIA is test of choice
* Viral loads and p24 assays should be reserved for suspected cases of acute seroconversion given high false pos rate
Counseling
* For 3 months following exposure HCW should avoid:
-unprotected sex
-donating blood
-sharing razors, toothbrushes
* HCW should consider stopping breast feeding (risk of perinatal transmission and drugs may get into breast milk)

Time to Seroconversion
* Most HCW seroconvert in 6-12 weeks with median time of 46 days
* 95% seroconvert within 6 months
* 100% seroconvert in one year
* Co-infection with HCV may delay HIV seroconversion

Acute Retroviral Conversion
* Symptomatic seroconversion develops in 50-90% of cases
* Average time from exposure to symptoms is 2-6 weeks
* ANY HCW who develops a flu-like illness in the follow up period should be encouraged to get HIV RNA testing

Resources
Conclusion

* People react very differently to exposures - be prepared for anything!
* The psychological impact of an exposure can be enormous
* Your patience and understanding may be the best PEP of all

Occupational Exposures to Bloodborne Pathogens.ppt