HCV Flashcards by Amalia Gazala

What is the infectious agent in hepatitis C?

Hepatitis C virus (HCV)

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Describe the HCV

enveloped, single-stranded RNA virus (family Flaviviridae)

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What family of viruses does HCV belong to?

Flaviviridae

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What characteristic of HCV contributes to immune evasion?

genetic diversity (multiple genotypes)

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Describe the environmental stability of HCV

remains infectious on surfaces for hours to days - enveloped virus (but less environmentally stable than HBV > 7days)

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What are the 2 forms of hepatitis C?

acute HCV infection and chronic HCV infection

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How will an acute HCV infection present?

asymptomatic

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What proportion of HCV infections are acute and clear spontaneously?

~20-30% acute, clear spontaneously

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What proportion of HCV infections progress to chronic disease?

~70-80% progress to chronic disease

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What conditions can result from chronic HCV infection?

cirrhosis and hepatocellular carcinoma

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What is the dental relevance of asymptomatic acute and chronic HCV infections?

patients may appear clinically well but still be infectious

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Why is hepatitis C relevant to dentistry?

blood borne virus transmitted through exposure to infected blood (sharps)
many infected individuals are asymptomatic (unaware)

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What puts dental professionals at risk of acquiring HCV?

sharps injuries, blood exposure

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Why is understanding HCV serology testing important?

exposure management
occupational health assessment
safe, non-discriminatory patient care

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Which hepatitis C tests are used in the UK?

anti-HCV antibody
HCV RNA (PCR test)

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What does anti-HCV antibody testing detect?

whether the patient has had an HCV exposure at any time (does not distinguish between current and past infection)

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Does a positive anti-HCV antibody test indicate a current or a past infection?

anti-HCV does not distinguish between a current or past infection

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How long after an HCV infection does the patient become positive for anti-HCV?

becomes positive 6-12 weeks after infection

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What is the implication of a positive anti-HCV result?

does not necessarily mean the patient is infectious (could be a past infection) - further testing is always required (HCV RNA / PCR test)

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What does the HCV RNA (PCR test) detect?

presence of active virus in blood

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What does a positive HCV RNA (PCR test) indicate?

current infection and infectivity

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How soon after HCV exposure is HCV RNA detectable?

detectable as early as 1-2 weeks after exposure

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What is the dental relevance of HCV RNA (PCR test)?

confirms whether a patient is currently infectious
used after occupational exposure to assess transmission risk

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What will the anti-HCV and HCV RNA test results be for a patient who has never been infected with HCV?

negative anti-HCV, negative HCV RNA test

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What will the anti-HCV and HCV RNA test results be for a patient with an acute HCV infection?

positive anti-HCV, positive HCV RNA test

What will the anti-HCV and HCV RNA test results be for a patient with a chronic HCV infection?

positive anti-HCV, positive HCV RNA test

What will the anti-HCV and HCV RNA test results be for a patient who's had a past infection (cleared)?

positive anti-HCV, negative HCV RNA test

What will the anti-HCV and HCV RNA test results be for a patient successfully treated for HCV?

positive anti-HCV, negative HCV RNA test

What is the duration of anti-HCV following a HCV infection (even after cleared / cured)?

anti-HCV remains positive for life

Rank the order of infectivity of HCV, HBV, HIV in needlestick injuries

HIV (0.3%) < HCV (3%) < HIV (30%)

What testing should be done for HCV following a significant sharps injury?

- baseline anti-HCV and HCV RNA testing - follow-up RNA testing to detect early infection

Is post-exposure prophylaxis available (PEP) for HCV?

no PEP

Why is early detection of HCV (e.g. follow-up HCV RNA test after sharps) important?

allows curative antiviral treatment

What is the HCV reservoir?

humans are the only reservoir

Which individuals are a reservoir for HCV?

individuals with an acute infection (usually asymptomatic), or a chronic infection (majority of cases)

What makes up the majority of the HCV reservoir?

individuals with a chronic HCV infection

Why can the HCV reservoir be considered as hidden?

many HCV infected individuals are undiagnosed

What is the dental relevance of the HCV reservoir?

patient's HCV status if often unknown - standard precautions apply to all

How many people have chronic HCV globally?

50 million people

Approximately how many new HCV infections are there annually?

1 million new infections annually

Approximately how many people died from HCV in 2022?

242 000

What is the treatment for HCV?

Direct-acting antiviral medicines (DAAs)

What percentage of HCV cases can be cured with direct-acting antiviral medicines (DAAs)?

over 95%

What inequalities are relevant to HCV?

access to diagnosis and treatment (DAAs) is low in hotspots worldwide

How many HCV cases were newly diagnosed in Scotland in 2024?

1351 cases (5% of which - 337 - in GGC NHS)

What percentage of HCV antibody diagnoses were amongst individuals residing in the most deprived quintile?

41% - inequality

What were the Scottish government HCV elimination targets for 2024/25?

What is Scotland's progression towards the Scottish Government HCV elimination targets?

3961 people were living with chronic infection by the end of 2024/25 (met reduced burden of infection

What percentage of HCV cases in England are in London?

31%

How many new HCV cases were diagnosed in London in 2022?

5345 new cases in 2022 (highest in last 10 years)

What is the biggest risk factor for HCV?

injecting drug use (IVDU)

What percentage of people who had ever injected drugs had anti-HCV antibodies (possibly had acute or is chronic)?

64%

What population group has the highest reports of hepatitis C in London in 2022?

males aged 35-54 years (68% of cases)

What is the portal of exit for HCV?

blood (main infectious fluid) - other bodily fluids contain very low or negligible viral levels unless visibly contaminated with blood

What is the dental relevance of HCV portal of exit?

blood-contaminated saliva during extractions, periodontal therapy, oral surgery is main concern

How does HCV transmission occur?

blood-to-blood exposure

What are the possible modes of HCV transmission?

- percutaneous exposure - iatrogenic transmission - vertical transmission - sexual transmission

How can percutaneous exposure occur?

- injection drug use - sharps / needlestick injuries - unsafe medical / dental procedures

How can iatrogenic transmission of HCV occur?

via contaminated equipment or blood products

Why is iatrogenic transmission of HCV via contaminated blood products rare in high income countries?

due to screening

What is vertical transmission?

transfer of disease from mother to child during pregnancy, childbirth or breastfeeding

What is the risk of HCV transmission via vertical transmission?

low risk overall

What is the risk of HCV transmission via sexual transmission?

inefficient / low

How is the risk of HCV transmission via sexual transmission increased?

increased risk with traumatic practices or co-infection (e.g. HIV)

What routes is HCV NOT transmitted by?

casual contact, food, water, respiratory routes

What is the dental relevance of HCV modes of transmission?

sharps handling and instrument decontamination - key control points

Although HCV transmission within dental settings has been rare, what are these instances linked to?

clear breaches in infection prevention and control (rather than routine care), reuse of instruments / injectable equipment

What is the most common direction of HCV transmission in dentistry?

patient-to-dental healthcare worker

How does patient-to-dental professional HCV transmission occur?

- needlestick / sharps injuries - cuts from contaminated instruments

What is the estimated transmission risk of HCV after a percutaneous exposure (from patient with active HCV infection)?

3% approx

What agreement outlines the measures to prevent sharp injuries?

Directive 2010/32/EU

Which regulation requires the implementation of the Directive 2010/32/EU principles, under UK law?

Health and Safety (Sharp Instruments in Healthcare) Regulations 2013

What are the 5 Directive 2010/32/EU principles?

1. duty to assess and control sharps risk 2. implement safe systems of work 3. training and information 4. reporting and follow up 5. documentation and policy

What does the first Directive 2010/32/EU requirement - duty to assess and control sharps risk - involve?

identifying where sharps are used, how injuries may occur, implementing measures to reduce risks (workflows, safer devices, ergonomic setups)

What does the second Directive 2010/32/EU requirement - implement safe systems of work - involve?

- avoiding unnecessary use of sharps - using safer sharps devices (e.g. ultra safety plus twist) - prohibiting recapping of needles - don't leave burs in handpieces, place USS on bracket table

What does the third principle of Directive 2010/32/EU - training and information - involve?

all staff must - receive training on sharps injury prevention - be aware of risks and safe handling procedures - understand how to respond in case of injury

What does the fourth Directive 2010/32/EU principle - reporting and follow-up - involve?

reporting and investigation into why injury occurred - appropriate occupational health assessment and follow-up, corrective action to prevent recurrence

What does the fifth Directive 2010/32/EU principle - documentation and policy - require from dental practices?

dental practices should have written policies on: - sharps risk assessment - safe device selection and use - training schedules -incident reporting and investigation

Where can guidance on written policies that dental practices should have be found?

SDCEP Practice Support Manual

Although rare, how could patient-to-patient HCV transmission in dentistry occur?

inadequate cleaning / sterilisation resulting in reused blood-contaminated instruments

Which procedures increase the risk of HCV patient-to-patient transmission?

oral surgery, periodontal surgery, endodontic procedures involving blood

What feature of HCV makes the correct decontamination of instruments essential?

HCV can survive in dried blood for hours to days

What is the risk of dentist-to-patient transmission of HCV?

extremely rare - no outbreak linked to infected dental professionals - risk is theoretical

What conditions are required for the theoretical HCV transmission from dentist to patient?

- active viremia - exposure-prone procedures - significant breaches in standard precautions

How is the dentist-to-patient route of HCV transmission negligilbe?

by adhering to standard precautions

What factors are associated with HCV transmission events?

- sharps injuries - inadequate PPE (esp eye protection) - poor instrument decontamination - lack of exposure reporting and follow-up - high background prevalence of HCV

Why is dental HCV transmission rare today?

- standard precautions applied to all patients - improved instrument reprocessing and sterilisation - single use items for injections - blood donor screening - increased diagnosis and curative antiviral treatment, lowering community viral load

What is the most significant HCV transmission route globally?

injecting drug use

Examples of unsafe medical care that are modes of HCV transmission

unscreened blood transfusions, reusing unsterilised / medical / piercing / tattoo equipment

What are the estimated risks of transmission of the 3 main BBVs following a significant percutaneous injury from an infected source patient?

HIV 1 in 300 (0.3%) HCV 1 in 30 (3.3%) HBV 1 in 3 (33% - if e-antigen +ve patient)

Although the rule of threes for BBVs are estimates, what factors does the actual risk of transmission depend on?

- type of exposure (e.g. depth of injury, amount of blood) - viral load (amount of virus in pt's blood) - immunity status of exposed person (e.g. HepB vaccine)

How common is acute HCV with jaundice?

uncommon - most acute cases are asymptomatic and undiagnosed

How is percutaneous inoculation with HCV prevented?

sharps awareness, needlestick protocols, eye protection, glove use

What percentage of infected HCV individuals have spontaneous clearance?

approx 15-25%

Which groups of patients are more likely to have spontaneous clearance of an HCV infection?

younger patients, females, strong innate immune responses

Does a cleared HCV infection result in protective immunity?

no - reinfection with a different variant of HCV is possible

How is a chronic HCV infection (majority of cases) defined?

persistent HCV RNA >6 months

What is the effect of a chronic HCV infection?

- often clinically silent for many years (reservoir) - progressive liver damage

Why does chronic HCV infection result in progressive liver damage?

due to ongoing low-grade inflammation

What factors influence the fibrosis progression from chronic HCV infection?

- alcohol use - co-infection (e.g. HIV) - metabolic disease

What are the possible complications of fibrosis progression in the liver (long term outcome of chronic HCV)?

cirrhosis, portal hypertension, hepatocellular carcinoma

What is the impact of direct-acting antivirals (DAAs)?

- cure >95% of chronic HCV infections - prevent progression if given early - curing reduces infectivity but does not restore immunity

Why is prevention of HCV critical?

no vaccine or PEP exists - importance of standard IP+C

What are the focuses of WHO in their strategy to eliminate Hepatitis C as a public health threat by 2030?

- reducing new infections by 90% - reducing deaths by 65% via prevention - increase testing - increase treatment

HCV Flashcards

(104 cards)