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Beyond Fear: Bloodborne Pathogens and the Health Care Worker

Beyond Fear: Bloodborne Pathogens and the Health Care Worker. National HIV/AIDS Clinicians’ Consultation Center National Clinicians’ Post-Exposure Prophylaxis Hotline. Scope of the Problem . Recent epidemiology of bloodborne pathogens (BBP) Recent epidemiology of occupationally acquired BBP

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Beyond Fear: Bloodborne Pathogens and the Health Care Worker

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  1. Beyond Fear: Bloodborne Pathogens and the Health Care Worker National HIV/AIDS Clinicians’ Consultation Center National Clinicians’ Post-Exposure Prophylaxis Hotline

  2. Scope of the Problem • Recent epidemiology of bloodborne pathogens (BBP) • Recent epidemiology of occupationally acquired BBP • How post-exposure management can affect delivery of care

  3. Recent United States Epidemiology • HIV • Estimated 800,000-900,000 people with HIV • 40,000 new cases each year • Hepatitis C • Estimated 3.9 million total US infections (1.8% of US population) • Hepatitis B • 750,000-1 million carriers in the US

  4. Recent Occupational Epidemiology • HIV • 57 documented occupational infections in U.S. health care workers, 138 possible infections • Hepatitis C • 1-2% of health care workers infected (same as general population) • Hepatitis B • 400/year in 1995 compared to 16,000/yr in 1983

  5. Exposure management makes a difference! • Health care workers put themselves at risk in their work. • Prevention of exposures is critical. • Appropriate treatment, including PEP, after exposures reduces risk. • Awareness of post-exposure options may allay fears of caring for infected patients.

  6. Components of Post-exposure Treatment • Crisis Management • Risk Assessment • Laboratory Assessment of Source • Post-Exposure Prophylaxis • Follow-up Care

  7. Case Slide • 27 year old nurse sustained a deep stick from a bloody needle after placing an IV. • The source patient was HIV+ and being treated with AZT/3TC/nelfinavir. His viral load was 122,000 several weeks earlier and he was admitted for bacterial pneumonia.

  8. Crisis Management • BBP exposures can be turning points for health care workers. • Extreme anxiety can be directly confronted. • Reassure without dismissing feelings. • Bridge gap between objective and subjective assessment. • Base approach on philosophy of advocacy for the worker.

  9. Case Slide • Due to the high risk nature of this exposure, this nurse was seen immediately by the infectious diseases consultant to occupational health. He consulted with several colleagues to choose the optimal regimen for PEP and to ensure that he was maintaining his objectivity.

  10. DETERMINING RISK Assessment of the Exposure Assessment of the Source

  11. Defining Exposure - PHS Definition • “…a percutaneous injury…or contact of mucous membrane or non-intact skin…with blood, tissue or other body fluids that are potentially infectious.” UpdatedPublic Health Service Guidelines for the management of Occupational Exposures to HBV, HCV and HIV and Recommendations for PEP. June 29, 2001.

  12. Defining Exposure - General Principles • HIV, HBV and HCV do not spontaneously penetrate intact skin. • Airborne transmission of these viruses does not occur. Beltrami, et al. ClinMicroRev July 2000.

  13. Defining Exposure: Infectious Body Fluids • Definitely infectious: • blood • semen • vaginal secretions • any visibly bloody body fluid

  14. Defining Exposure: Infectious Body Fluids • Potentially infectious: • cerebrospinal fluid • synovial fluid • pleural fluid • peritoneal fluid • pericardial fluid • amniotic fluid • pus

  15. Defining Exposure: Infectious Body Fluids • Not infectious unless visibly bloody: • feces, urine • nasal secretions, sputum • saliva • sweat • tears • vomitus

  16. Defining Risk - Per-exposure Estimates • HIV • percutaneous0.3% • mucocutaneous 0.09% • HCV • percutaneous 1.8% • HBV • percutaneous • eAg+ 40% • eAg- 1.5-10%

  17. Defining RiskPublic Health Service Guidelines • Needlestick • Less severe (eg. Solid needle and superficial injury) • More severe (eg. Large-bore hollow needle, deep puncture, visible blood on device, or needle used in patient’s artery or vein) • Mucous membrane and nonintact skin • Small volume (i.e. a few drops) • Large volume (i.e.. major blood splash)

  18. Stratifying Risk - Case-control Study

  19. Stratifying Risk - In vitro Studies • In vitro studies • Larger needles and deeper sticks are associated with larger blood volume transfer. Mast et al. JID 1992 168:1589-92 • Gloves reduce blood volume transfer. • Bennett, Howard. J.Am.Coll.Surg. 1994 178:107-110 • Needles used for injection likely less risky than those used to draw blood.

  20. Stratifying Risk • Splash to mucous membrane or non-intact skin. • Longer exposure to higher volume likely more risky. • Bite exposures. • Bite victim not at risk unless blood in saliva. • Biter has sustained blood to mucous membrane exposure.

  21. Stratifying Risk - Source Assessment • If source is HIV+ • What is viral load/stage of disease? • If HIV status is unknown • What is history of risk factors? • Any symptoms of primary HIV infection? • What is history of testing? • If source is unknown • What is prevalence where exposure occurred? • How long has sharp been environmentally exposed?

  22. Source Assessment: Laboratory Management • Do not delay PEP while awaiting source patient laboratory results. The decision to start PEP is based on the clinical risk assessment. • Consider testing options: • rapid vs standard HIV antibody test kit • antibody testing vs direct virus assay • no option currently to test discarded needles

  23. Source Assessment: Laboratory Management • Rapid EIA should be considered. • A negative result allays anxiety and prevents overuse of PEP. • The false positive rate is higher than the standard EIA. This is particularly significant in low risk populations. • All positive tests must be confirmed with a Western Blot or Immunofluoresence assay.

  24. Source Assessment: Laboratory Management • Standard EIA may be preferred, especially if it can be performed in 24-48 hours. • Direct virus assays (p24 or viral load) not recommended, unless source is suspected to be in the window period. • Not standardized for diagnosis. • High false positive rate (2-5%).

  25. Source Assessment: Addressing the Window Period • Median time to seroconversion is estimated at 4 weeks. • If source is HIV- and has no history of recent (last 3 months) risk behavior and no symptoms of primary HIV infection, consider HIV ruled out.

  26. PEP for HIV - General Principles • Most exposures do not result in transmission of HIV, so risk and benefit must be weighed carefully. • Consider risk of exposure and source. • Consider factors in the health care worker. • concurrent illness or medication. • pregnancy or breastfeeding.

  27. PEP likely beneficial • High risk exposure • Known positive source • High risk source • No delay to rx • Choice of drugs minimizes toxicity • Side effects may outweigh benefits • Low risk exposure • Low risk source • Found needle • Delay (>72 hrs) • Drug interactions/co-existing medical conditions. • Pregnancy???

  28. PEP for HIV: Plausibility • Rhesus macaque model: • intravaginal exposure to SIV. • at 24 hours, SIV detected in vaginal dendritic cells. • by 48 hours, SIV detected in regional lymph nodes. • by 5 days SIV detected in peripheral blood. • The time to disseminated infection provides a window for intervention.

  29. PEP for HIV: Efficacy • Macaque model: IV inoculation with SIV. • PMPA prophylaxis started 48 h before, 4 h after or 24 h after inoculation and continued for 28 days. Controls untreated. • No treated animal were infected; all controls were infected. Tsai CC et al. Science270:1197-1199.

  30. PEP for HIV: Efficacy • ACTG 076: randomized controlled trial to assess ability of AZT to reduce perinatal transmission in humans. • Risk of vertical transmission reduced from 22.6% in placebo treated controls to 7.6% in treatment arm (AZT alone). • Reduction in viral load only partially explains reduction in transmission.

  31. PEP for HIV: EfficacyNY DPH Perinatal Transmission

  32. PEP for HIV: Timing • Macaques inoculated IV with SIV • PEP with PMPA for 28 d initiated 24, 48 and 72 h after inoculation. Controls mock treated. • All controls infected • All animals treated at 24 h protected • Half of the animals in the other treatment groups showed persistent viremia. • Tsai CC et al. J Virology 1998

  33. PEP for HIV: Timing • Rhesus monkeys inoculated IV with SIV • AZT PEP initiated 1, 8, 24 and 72 h after inoculation. Controls mock treated • Infection prevented in 1/5 in the 1 and 8 h groups • Antigenemia delayed and reduced in all other treated animals. • Martin LN et al. JID 1993

  34. PEP for HIV: Timing • SCID-hu mice inoculated IV with HIV • AZT PEP initiated 0.5, 1, 2, 4, 8, 24, 36, and 48 h later. • All mice treated at 0.5, 1, and 2 h protected. • 80% of mice treated at 8 h protected. • 40% of mice treated at 24 h protected. • No effect of treatment initiated at 48 h. Shih CC et al. JID 1991

  35. PEP for HIV: Timing • 13 yo girl transfused w/ one unit of blood from donor in the window period • Infection risk estimated at 100% • 3-drug PEP initiated 50 hours post-transfusion, continued for 9 months • No evidence of HIV infection 15 months later Ann Int Med 2000;133:31-4

  36. PEP for HIV: Duration • Macaques inoculated IV with SIV • PEP with PMPA initiated at 24 h after exposure, and continued for 3, 10 and 28 d. • All animals treated for 28 days protected. • ¼ animals treated for 10 days had persistent infection, ¾ with antibody response, • 2/4 animals treated for 3 days had persistent infection, 4/4 with antibody response.

  37. PEP for HIV: Choosing a regimen • Basic regimen? • Alternate basic regimen? • Expanded regimen? • Protease inhibitors • NNRTIs • Abacavir • Drugs for use with consultation?

  38. Case slide • The exposed health care worker was in good health, on no medications and not pregnant or breastfeeding. • After extensive counseling and discussion, a regimen of ddI/d4T/nevirapine was initiated.

  39. PEP Regimen Options Basic Regimens • For use after low risk exposure to HIV+, ARV naïve source, or when source not known HIV+. • AZT 300 mg BID+3TC 150BID • Side effects: nausea, headache, fatigue, rare anemia from AZT

  40. PEP Regimen OptionsAlternative Basic Regimens • For use when source virus likely resistant to or health care worker intolerant of Basic Regimen • ddI 200mg BID(400qD)+d4T 40 mg BID • d4T 40 mg BID+3TC 150 BID • AZT 300 mg BID+ddI 200 mg BID(400qD) • Side effects: ddI – nausea, diarrhea, pancreatitis, neuropathy. d4T - neuropathy

  41. PEP Regimen OptionsExpanded Regimens • For use after high risk exposures to HIV+ source or when source virus resistant. • Basic regimen plus one of the following: • Protease inhibitor • Dual PI • NNRTI • Third nucleoside (abacavir)

  42. PEP RegimensWhy NOT expanded regimen? • Transmission is rare. • No evidence that 3 drugs is better than 2 (or 2 better than 1). • 3 drug regimens associated with more toxicity and decreased adherence.

  43. PEP Registry: 4-6 week follow upn=449

  44. PEP Registry: Reasons for discontinuation* (48%) (50%) (31%) (13%) (2%) (5%) *Reasons not mutually exclusive

  45. nelfinavir 750 mg TID/1250 BID OR indinavir 800 mg q 8hr. Nelfinavir - diarrhea, nausea, vomiting, increased LFT’s Indinavir - nausea, vomiting, increased LFT’s, kidney stones, difficult adherence. Expanded Regimen - Single Protease Inhibitor

  46. Saquinavir + Ritonavir Indinavir + Ritonavir Amprenavir + Ritonavir Lopinavir + Ritonavir Dual PIs may have added activity. BID regimens more convenient. Potentially increased toxicities and complex drug interactions. Expanded Regimen - Dual PI

  47. Efavirenz 600 mg qD Nevirapine not recommended. Potent agent in treatment. >50% of patients have CNS effects. Teratogenic in monkeys Expanded Regimens - NNRTI

  48. Case slide • She tolerated the regimen well for 14 days when she noted the onset of fever to 101 F, sore throat, disseminated lymphadenopathy (most marked cervically), a fine macular rash on her trunk, and arthralgias. She was seen immediately by the ID consultant who noted no thrush, or oral/genital ulcers.

  49. Symptom Management in PEP: Acute infection vs. drug effect • Symptoms of acute HIV or hepatitis can resemble those of an adverse drug reaction (fever, rash, abnormal liver function tests). • Follow patients closely with complete physical, medication adjustment, and targeted laboratory assessment.

  50. At baseline and q 2 weeks while on PEP. CBC Renal panel LFT’s UA if on IDV Consider glucose if on PI. Baseline serology Follow-up serology at 6 weeks, 3 months, 6 months post exposure. Can recheck at 1 year. May be more important if HCW infected with HCV from same exposure. PEP Laboratory Monitoring

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