L44 Blood borne viral infections (HBV, HCV, HIV)

Question 1

List at least 4 routes of transmission for Hep B.

Answer 1

1. Vertical
2. Horizontal
   - Sexual
   - Blood-borne
   - blood and bodily fluid (transfusion, organ transplant)
   - IVDU
   - sharps injury
   - tattoo, beauty plaza

Question 2

Clinical course of Hep B after exposure:

1. Incubation period?
2. What stages? (symptoms?)

Answer 2

1. 2-6 months inbubation period
2. Acute hepatitis
   - not all infections go through this stage
   - depends on age and immune status
   - most infections in neonates and childhood are asymptomatic

• adults: 30-50% asymptomatic
• fever, jaundice, malaise
• fulminate hepatitis <1%

3. Full recovery //
   Chronic hepatitis (long asymptomatic phase 20-40 years)
   - cirrhosis
   - HCC

Question 3

Risks factors for developing chronic hepatitis in Hep B infection?

Answer 3

1. Asymptomatic primary infection
2. Immunocompromised (post-transplant)
3. Male > female
4. Infant > children&raquo_space; adults

Question 4

Hep B carriers are 200x higher risk for?

Answer 4

Hepatocellular carcinoma

Question 5

In areas with high and intermediate levels of prevalence of Hep B, infection is maintained by which route?
How about low level of prevalence?

Answer 5

High: by vertical transmission
Low: by horizontal trasmission/ acquired overseas/immigrants

Question 6

In Hong Kong, why younger generation has much lower HBV carrier rate?

Answer 6

Universal immunisation started in 1988

almost 100% coverage

Question 7

What are the markers for acute HBV infection? ***

What are the possible clinical signs and symptoms?

Answer 7

1. HbsAg
2. Anti-HBc IgM (anti-core IgM)

• Jaundice, fever, malaise

Question 8

What are the markers for chronic HBV infection/carriers?

Answer 8

1. HbsAg > 6 months

2. +/- HBeAg (‘E antigen’)

Question 9

1. What are the marker of natural HBV infection (present in carrier, and those who have recovered from previous infection) ?
2. Marker of recovery from previous infection / vaccination?

Answer 9

1. Anti HBc-Ag IgG

(will not appear in vaccination!)

2. Anti-HBs IgG (vaccination)

Question 10

Which of the following about the vaccine for Hep B is incorrect?

A. It is universal to all newborns since 1988
B. 3 doses at 0,1,6 months
C. Recombinant vaccine based on HBcAg
D. Post-vaccination check and regular booster is not routinely required
E. Post-vaccination check for healthcare worker is required to guide management after sharps injury

Answer 10

C

- based on HBsAg

Question 11

What is the post-exposure prophylaxis for Hep B? (1)

When is it given? (2)

Answer 11

Hepatitis B immunoglobulin (HBIG)
- immediate, but short duration (~1 month) protection

Given in:

1. Newborns of HBsAg+ve mothers
2. Sharps injury for non-immune HCWs

Question 12

What are the treatment for chronic HBV?

Answer 12

1. Peg-interferon
2. Nucleotides analogues
   - Entecavir
   - Tenofovir

• Tenofovir is used now in pregnant lady with high viral load to decrease maternal fatal transmission

Question 13

What are the differences between HBV and HCV in

1. Transmission
2. Acute infection - symptomatic?
3. Progress to chronic carrier
4. Outcome of chronic infection

Answer 13

1. HBV: Blood, sexual, vertical; HCV: same but less infectious
2. HBV: age-dependent symptomatic ratio (young is asymptomatic); HCV: mostly asymptomatic
3. HBV: uncommon in adults; HCV: common, >80%

4, both: Chronic active hepatitis, cirrhosis, liver cancer

Question 14

HCV vaccine and passive immunisation?

Answer 14

Not available!

c. f. HBV
- vaccine + HBIG for post-exposure prophylaxis

Question 15

General population of HCV carriers in HK is 0.3%, with which group of patients most prevalent?

Answer 15

IVDA > 50%

Question 16

What is the routine tests for HCV antibody?

Screening test?

Answer 16

1. total antibodies/ HCV IgG antibodies
2. HCV core antigen (95% detectable if HCV RNA+ patients)

Screening: EIA (ELISA x1-2)

+ confirmatory essays:
- recombinant immunoblot assay (RIBA), less commonly used now

Question 17

Treatment available for HCV?

Answer 17

1. Peg-interferon and ribavirin
   - Sustained virological response (SVR): ~60-80% depending on viral genotypes
2. Direct acting antiviral agents (DAA)
   - protease inhibitors, NS5A inhibitors and NS5B inhibitors (expensive)

Question 18

Hepatitis D can be protected by Hep B prevention measures. T/F?

Answer 18

T
- Coinfection/ superimposed infection with HepB

• with HBsAg + HDV genome (RNA)

Question 19

HIV stands for? What family does it belong to?

Answer 19

Human Immunodeficiency virus

• Retrovirus
• ssRNA > dsDNA (provirus)
• using reverse transcriptase (target of antivirals)
• viral dsDNA integrates into host genome, once infected, difficult to clear
• polyproteins cleaved by viral protease into component proteins and assemble to mature virion

Question 20

Route of transmission for HIV? (3)

Answer 20

1. Sexual
   - homo, heterosexual
   - increased by genital ulcers (syphilis, HSV)
2. Vertical
   - during delivery and breastfeeding (15-40%)
   - reduced by antiviral treatment during pregnancy)
3. Blood and body fluid
   - transfusion, transplant, sharps injury, tattoo, beauty plaza

Question 21

What are the different phases for HIV?

Answer 21

1. Acute phase (2-4 weeks)
2. Latent phase (6-10 years)
3. AIDS (2-3 years)

Question 22

Which of the following about acute phase of HIV is correct?
A. several weeks after exposure
B. ~30% develop acute disease syndrome/sero-conversion illness
C. Fever, enlarged lymph nodes, non-specific flu-like
D. self-limiting
E. High risk of transmission

Answer 22

All correct

E: due to high level of virus in body

Question 23

Which of the following about the latent phase of HIV is incorrect?
A. Clinical asymptomatic
B. Level of virus is more than acute phase, highly infectious
C. CD4-T cells are destroyed by virus, its level decreases gradually

Answer 23

B

- Level of virus is lower, but still highly infectious

Question 24

AIDS phase of HIV infection:
A. CD4-T cells decreased to <200
B. Immune function is impaired

What are the opportunistic infections? (4)
What are the associated malignancies? (3) - rare

Answer 24

Opportunistic infections

1. Zoster
2. TB
3. Toxoplasma
4. Cryptococcus
5. Pneumocystis carinii pneumonia… (others: CMV retinitis, disseminated MAC)

Malignancies

1. Kaposi’s sarcoma (HHV-8)
2. Lymphoma (NHL - EBV)
3. CNS tumor
   (others: cervical cancer HPV; anal cancer HPV)

Question 25

How do we detect HIV? | When does HIV antibody develop?

Answer 25

- Early phase of detection = infectious state but antibody not yet developed, 2-8 weeks by ELISA antigen-antibody HIV antibody develop within 3 months (but do not want to wait so long to diagnose)

Question 26

``` Risk factors for HIV? A. Heterosexual contact B. Homosexual contact C. Increase in MSM D. Perinatal but rare E. IVDU but uncommon ```

Answer 26

All of the above A: 30% B: 40%

Question 27

Treatment for HIV?

Answer 27

HAART - Highly active antiretroviral therapy - combination of drugs 雞尾酒療法 - lower viral load to undetectable level - virus re-emerges when HAART is stopped (still incurable) ``` examples: reverse transcriptase inhibitors protease inhibitors integrase inhibitors entry inhibitors ```

Question 28

Infection control and practices for blood-borne infection to minimise accident?

Answer 28

1. Universal precaution: every patient is treated as if infected 2. Blood and body fluid precaution 3. Standard precaution = 1+2 - apply to all patients 4. Engineering controls (sharp disposal containers) 5, Work place control

Question 29

Primary prevention for blood-borne infections? Management of accidents?

Answer 29

Primary prevention 1. Vaccination for HBV 2. Post-vaccination check 3. No vaccine for HIV, HCV Management 1. Immediate wound care 2. Reporting 3. Post-exposure prophylaxis 4. Active and medical FU

Question 30

Which of the following are immediate wound care practice? A. Wash off blood under running water with skin antiseptics B. Avoid brushes C. Wash wounds with soap and water without scrubbing D. Encourage bleeding for all wounds E. Disinfect and dress wound F. Remove contact lens if eye exposure, flush with water or saline

Answer 30

D is incorrect, only if minor wounds Also need to report

Question 31

Advice and medical follow up for sharp injuries? A. Avoid pregnancy, blood donation and practice safe sex B. Aware of symptoms of hepatitis and HIV seroconversion illness C. Follow-up HCV and HIV tests at 3 months D. AntiHBs test at 1-2 month if vaccinated E. Anti-HIV test at 6 months if received anti-retroviral agents

Answer 31

All of the above

Question 32

What can be considered for HIV post-exposure prophylaxis ?

Answer 32

Anti-retroviral - effectiveness depends on timing of initiation, preferably within 1-2 hours - should not be delayed, starter pack available at A&E - 3 drugs combination - 28 days course, common S/E - Test for HIV antibody at 3 months - addition 6 month test if delayed sero-conversion is suspected e.g. had received anti-viral for PRP/ source is HCV/HIV co-infected