Hepatitis, HIV & AIDS Flashcards
What are the clinical features of hepatitis A?
Incubation period 2-7 wks
Illness brief and self-limiting
Mortality
What is the vaccine for hepatitis A?
Formaldehyde-inactivated
Prepared from the GBM or HM175 strain of hep A
Single dose - antibody for 1 year
Booster dose at 6 to 12 mnths - immunity for 10 years
Is there a vaccine for hepatitis B?
There is an effective vaccine but not an effective treatment
How many subtypes of hepatitis B are there?
8
What is the hepatitis B surface antigen? (HBsAg)
Produced when the virus replicates
Not actually infectious
What is the hepatitis Be antigen? (HBeAg)
Derived from HBcAg (hep B core antigen)
Present in plasma
Marker of high infectivity
Which hepatitis virus is not typically transmitted via the blood?
Hepatitis A.
Transmitted via the faecal-oral route, person to person, food-borne and water-borne.
How is hepatitis B transmitted?
Blood-borne - IV drug use, haemodialysis
Sexual
Perinatal - infants born to infected mothers
Who is at risk of contracting HBV?
Neonates - 90 to 100% immune system not fully developed
Children - 20 to 40%
HIV positive - 21%
Adults -
HBV can be acute or develop into chronic disease, what does this entail?
Chronic persistent/active hepatitis leads to:
Cirrhosis
Extrahepatic disease e.g. glomerulonephritis
Hepatocellular carcinoma
Death
How can your body naturally recover from HBV?
Anti-HBe and andti-HBs are produced inhibiting the production of HBeAg and HBsAg
What are the immunisation options for HBV?
Passive - HB immunoglobulin, used for single acute exposure in non immune individual within 48hrs
Vaccine - highly immunogenic, no booster required if person responds
Active - HBsAg adsorbed on aluminium hydroxide adjuvant administered intramuscularly, 3 doses (0, 1, 6 months), protection is good, response not always good
What is the Tx for HBV?
Aim is to achieve sustained viral suppression
IV interferon
Lamivudine
Adefovir
Entecavir
Response to Tx is variable and often disappointing
How many genotypes is there of HCV?
6
Is there a vaccine for HCV?
No vaccine available
What is the Tx for HCV?
No completely effective Tx.
Interferon alpha in combo with ribavirin, plus boceprevir or telaprevir.
Duration varies depending on the genotype - longer for genotype 1.
How is HCV transmitted?
Blood - IV drug use, organ/tissue transplant
Sexual
Vertical - mother to child
Undefined routes - saliva?
What are the clinical features of acute HCV?
Mild
25% experience jaundice
What are the clinical features of chronic HCV?
Indolent & slow progression over 20 years
Mild hepatitis to cirrhosis
Link with Hepatocellular carcinoma
How would you diagnose HCV?
ELISA - enzyme linked immunosorbent assay
RIBA - recombinant immunoblot assay
PCR - for detection of HCV RNA (viral genome)
Liver biopsy
What is hepatitis delta virus?
Defective small RNA virus
Can only cause disease in association with hep B as it produces its antigen coat
Vaccine & Tx for hep B also protect against hep D
How is HDV transmitted?
bodily fluids
What is hepatitis E?
Very similar to hep A but there is no vaccine
How is hep E spread?
Faecally contaminated drinking water
Epidemic and sporadic forms
What are the clinical features of hep E?
Mainly young adults (15-40 years)
Usually self-limiting acute disease
High mortality (up to 20%) in pregnancy
No chronic disease
If a dentist contracts Hep C can they still practice?
No
If a dentist contracts Hep B can they still practice?
No if HbeAg +ve.
Yes if HbeAg -ve & HBsAg +ve.
Viral load must be
If a dentist contracts HIV can they still practise?
Yes.
Must be on cART & plasma viral load
What should you do in the event of a needle-stick injury?
Encourage bleeding by squeezing and applying pressure
Wash (DO NOT scrub) with warm water and soap
Assess injury - deep, shallow, clean?
Assess risk of blood source
Report according to local policies
Prophylaxis if necessary/available
What’s more infective - Hep B or HIV?
Hep B is 100x more infective than HIV
