MPL 202 MIDTERM 2

• Describes common blood-borne infections for healthcare workers.
• This explains infection routes, and reducing infection risk with pre- and post-exposure interventions.
• Timing is critical during blood and bodily fluid exposure.

Needlestick injuries

• Injuries involving hollow-bore needles, which can contain more pathogens than sharps.
• These can occur during accessing IV lines, transferring specimens, transferring equipment.
• Risk Factors include collisions, inserting or removing a needle, and during or after disposal.
• Safe disposal is key, sharps containers should be at POC.
• Avoid recapping needles, clean up as needed.
• Common causes include carelessness, being stuck by another, or rushing.

Sharps injuries:

• This involves solid sharps during use, processing specimens, collisions, manipulating sharps in the patient.
• Risks include handling equipment, and suture needle handling.
• Risks after use include sharps left in unusual locations, and during cleanup or disposal.

Hierarchy of controls

• Elimination is most effective, removing the hazard.
• Substitution replaces the hazard.
• Engineering controls isolate people from hazards.
• Administrative controls change work processes to reduce risk.
• PPE protects workers.
• Elimination/substitution can reduce needle/sharp use.
• Engineering controls isolate hazards using sharps disposal containers.
• Administrative controls include training and processes, like avoiding recapping.

Safety Syringes

• Ask for safety syringes if unavailable.
• Occupational Health and Safety Act requirements in Ontario apply.

Pathogens

• Needlestick/Sharps injuries can transmit pathogens, most concerning are HBV, HCV, and HIV.
• HBV has a 30% chance of infection; vaccination greatly reduces this risk.
• HCV has a 3% chance of infection.
• HIV has a 0.3% chance of infection.

Hepatitis B Virus (HBV)

• HBV causes hepatitis, cirrhosis, liver failure, and liver cancer.
• Prevalence is about
• Transmission is primarily through blood.
• Incubation is 6 weeks to 6 months, averaging 3 months.
• Chronic infection is likely if the virus persists over 6 months.
• Chronic infection occurs in over 90% of infants, and 5-10% in adults.
• Antiviral management is available, but there is no cure.

Hepatitis C Virus (HCV)

• Causes hepatitis, cirrhosis, liver failure, and liver cancer.
• Prevalence is 1-1.5% in Canada, higher in marginalized communities.
• Transmission occurs primarily through blood.
• Incubation is 2 weeks to 6 months, averaging 2 months.
• 60-70% become chronically infected, 30% clear the virus.
• Curative therapy has been available since 2014 with direct-acting antivirals.

Human Immunodeficiency Virus (HIV)

• Untreated HIV leads to AIDS, opportunistic infections, and cancers.
• Prevalence is 0.2% in Canada, higher among IV drug users and MSM in Toronto.
• Transmission occurs primarily through blood and unprotected sex.
• Incubation is 1-2 weeks, acute HIV syndrome presents.
• Pathogenesis involves the destruction of CD4+ immune cells over 10 years.
• Effective treatment is available with HAART, but there is no cure.

Blood-borne pathogens summary

• Symptoms may not accompany HBV, HCV, HIV infections.
• Blood-borne infection risk can be high, higher among non-vaccinated populations.
• HBV, HCV, and HIV can cause chronic, life-changing diseases.
• Treatment can improves QoL for those infected.
• Pre- and post-exposure measures are available.

Pre-exposure prevention

• Prevent NSI with routine precautions.
• Vaccines are available for HBV but not HIV or HCV,.
• HBV vaccine is 95-100% effective, publicly funded.
• The first dose is given in grade 7, the second 4 months later.

HBV Vaccine

• Vaccine contains Hep B surface antigen (HBsAg).
• HBsAg immunization produces Hep B surface antibody (HBsAb).
• HBsAb neutralizes HBsAg, preventing infection.
• Completing the HBV vaccine series is enough evidence of protection,.
• Exceptions include immunocompromised individuals, those with chronic renal disease, or on dialysis, and healthcare professionals.
• Antibody response of ≥ 10 IU/mL needs documenting in HCP.
• Confirmation means protection for life.
• Booster doses match protective levels.
• Amnestic immunity is where the immune system forgets how to fight off pathogens, such as after a measles infection
• Titer check if Ab falls lower and give booster
• If vaccinated don't develop immunity following 2 doses
• If non-responder→complete second vaccination series, then retest, third dose, retest → Counsel for alt-risk reduction

Approach to needlestick injury

• Allow to bleed, wash site, proceed to ED or OccHealth clinic, report Exposure.
• Determine HBV vaccination history and immune status,.
• Assess disease status, fluid involved, puncture depth, if hollow bore needle vs not.
• Get consent for HBV, HCV, HIV testing, lab samples should be STAT
• If testing refused then court order must be obtained

Lab Results

• Exposed baseline is Negative = repeat testing at 3 weeks, 6 weeks, 3 months post-exposure
• Window period of blood-borne infections:
• HBV: 4-12 weeks post Exposure
• HCV: 1-10 weeks post Exposure
• HIV 2-4 weeks post Exposure
• If HCV RNA is detectable is positive, repeat HCV RNA in 6 months

Acute HCV Infection

• HCV Ag detects virus itself, Anti HCV develops 6-8 weeks post-expsoure
• Most infections Asymptomatic Seroconversion is where to detect antibodies at
• Interferon for tx if undetectable HCV RNA is more than 6 mths
• Viral clearance where anti HCV depletes over time once cleared.
• RNA test more accurate shows up faster, if none at 3 wks repeat til 6 mths, if antibodies present Antibodies ween over time until you get 0,

Limitations of serology

• False +, - and Cross-reactivity with similar organisms and EBV Infections can tamper results.
• Diet, human and heterophile antibodies
• Immunosuppresion all affect serology results
• Post exposure prophylaxis to needlestick
• HBV vaccine if <10IU/mL give HBIg non-respionder
• HCV No PEP or vaccine, only treat if become chronically infected
• HIV PEP for high risky exposures, dose within 72 hours,
• Counselling while waiting test results, barriers, do no donate, share items, cuts covered and wait
• Body fluid exposure same as needle but lower risk proceed to ED