L44 Blood borne viral infections (HBV, HCV, HIV) Flashcards
List at least 4 routes of transmission for Hep B.
- Vertical
- Horizontal
- Sexual
- Blood-borne
- blood and bodily fluid (transfusion, organ transplant)
- IVDU
- sharps injury
- tattoo, beauty plaza
Clinical course of Hep B after exposure:
- Incubation period?
- What stages? (symptoms?)
- 2-6 months inbubation period
- 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%
- Full recovery //
Chronic hepatitis (long asymptomatic phase 20-40 years)
- cirrhosis
- HCC
Risks factors for developing chronic hepatitis in Hep B infection?
- Asymptomatic primary infection
- Immunocompromised (post-transplant)
- Male > female
- Infant > children»_space; adults
Hep B carriers are 200x higher risk for?
Hepatocellular carcinoma
In areas with high and intermediate levels of prevalence of Hep B, infection is maintained by which route?
How about low level of prevalence?
High: by vertical transmission
Low: by horizontal trasmission/ acquired overseas/immigrants
In Hong Kong, why younger generation has much lower HBV carrier rate?
Universal immunisation started in 1988
almost 100% coverage
What are the markers for acute HBV infection? ***
What are the possible clinical signs and symptoms?
- HbsAg
- Anti-HBc IgM (anti-core IgM)
- Jaundice, fever, malaise
What are the markers for chronic HBV infection/carriers?
- HbsAg > 6 months
2. +/- HBeAg (‘E antigen’)
- What are the marker of natural HBV infection (present in carrier, and those who have recovered from previous infection) ?
- Marker of recovery from previous infection / vaccination?
- Anti HBc-Ag IgG
(will not appear in vaccination!)
- Anti-HBs IgG (vaccination)
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
C
- based on HBsAg
What is the post-exposure prophylaxis for Hep B? (1)
When is it given? (2)
Hepatitis B immunoglobulin (HBIG)
- immediate, but short duration (~1 month) protection
Given in:
- Newborns of HBsAg+ve mothers
- Sharps injury for non-immune HCWs
What are the treatment for chronic HBV?
- Peg-interferon
- Nucleotides analogues
- Entecavir
- Tenofovir
- Tenofovir is used now in pregnant lady with high viral load to decrease maternal fatal transmission
What are the differences between HBV and HCV in
- Transmission
- Acute infection - symptomatic?
- Progress to chronic carrier
- Outcome of chronic infection
- HBV: Blood, sexual, vertical; HCV: same but less infectious
- HBV: age-dependent symptomatic ratio (young is asymptomatic); HCV: mostly asymptomatic
- HBV: uncommon in adults; HCV: common, >80%
4, both: Chronic active hepatitis, cirrhosis, liver cancer
HCV vaccine and passive immunisation?
Not available!
c. f. HBV
- vaccine + HBIG for post-exposure prophylaxis
General population of HCV carriers in HK is 0.3%, with which group of patients most prevalent?
IVDA > 50%
What is the routine tests for HCV antibody?
Screening test?
- total antibodies/ HCV IgG antibodies
- HCV core antigen (95% detectable if HCV RNA+ patients)
Screening: EIA (ELISA x1-2)
+ confirmatory essays:
- recombinant immunoblot assay (RIBA), less commonly used now
Treatment available for HCV?
- Peg-interferon and ribavirin
- Sustained virological response (SVR): ~60-80% depending on viral genotypes - Direct acting antiviral agents (DAA)
- protease inhibitors, NS5A inhibitors and NS5B inhibitors (expensive)
Hepatitis D can be protected by Hep B prevention measures. T/F?
T
- Coinfection/ superimposed infection with HepB
- with HBsAg + HDV genome (RNA)
HIV stands for? What family does it belong to?
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
Route of transmission for HIV? (3)
- Sexual
- homo, heterosexual
- increased by genital ulcers (syphilis, HSV) - Vertical
- during delivery and breastfeeding (15-40%)
- reduced by antiviral treatment during pregnancy) - Blood and body fluid
- transfusion, transplant, sharps injury, tattoo, beauty plaza
What are the different phases for HIV?
- Acute phase (2-4 weeks)
- Latent phase (6-10 years)
- AIDS (2-3 years)
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
All correct
E: due to high level of virus in body
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
B
- Level of virus is lower, but still highly infectious
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
Opportunistic infections
- Zoster
- TB
- Toxoplasma
- Cryptococcus
- Pneumocystis carinii pneumonia… (others: CMV retinitis, disseminated MAC)
Malignancies
- Kaposi’s sarcoma (HHV-8)
- Lymphoma (NHL - EBV)
- CNS tumor
(others: cervical cancer HPV; anal cancer HPV)
How do we detect HIV?
When does HIV antibody develop?
- 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)
Risk factors for HIV? A. Heterosexual contact B. Homosexual contact C. Increase in MSM D. Perinatal but rare E. IVDU but uncommon
All of the above
A: 30%
B: 40%
Treatment for HIV?
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
Infection control and practices for blood-borne infection to minimise accident?
- Universal precaution: every patient is treated as if infected
- Blood and body fluid precaution
- Standard precaution = 1+2
- apply to all patients - Engineering controls (sharp disposal containers)
5, Work place control
Primary prevention for blood-borne infections? Management of accidents?
Primary prevention
- Vaccination for HBV
- Post-vaccination check
- No vaccine for HIV, HCV
Management
- Immediate wound care
- Reporting
- Post-exposure prophylaxis
- Active and medical FU
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
D is incorrect, only if minor wounds
Also need to report
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
All of the above
What can be considered for HIV post-exposure prophylaxis ?
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
