Hepatitis A virus: Difference between revisions
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− | == |
+ | ==Background== |
− | === |
+ | ===Microbiology=== |
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{| class="wikitable" |
{| class="wikitable" |
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− | ! |
+ | !IgM!!IgG!!Interpretation |
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+ | |–||–||No recent infection (unless in the incubation period). No prior infection or vaccination. |
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+ | |–||+||No infection. Prior infection or vaccination. |
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+ | |?||+||Cannot rule out active infection. Prior infection or vaccination. |
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+ | | +||+/–||Acute or recent infection. IgM positive from 2 weeks until 3-12 months. IgG positive from 8-12 weeks and remains positive for lifetime. |
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+ | == Prevention == |
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+ | |||
+ | === Vaccination === |
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+ | |||
+ | * Vaccination is indicated for people at increased risk of acquiring hepatitis A, or at increased risk of severe disease |
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+ | ** Travellers to endemic countries |
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+ | ** People with chronic liver disease |
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+ | ** Men who have sex with men |
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+ | ** People who use recreational drugs |
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+ | ** People living in communities with outbreaks or endemic hepatitis A |
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+ | ** Close contacts of children adopted from endemic countires |
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+ | ** Military personnel and humanitarian relief workers |
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+ | ** People receiving repeated doses of plasma-derived clotting factors |
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+ | ** Laboratory workers studying hepatitis A |
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+ | ** Zookeepers, veterinarians, and researchers who interact with non-human primates |
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+ | * Vaccination requires two doses spaced at least 6 months apart |
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+ | * It provides immunity for decades, and possibly for life |
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+ | * Often given combined with [[hepatitis B vaccine]] (HAHB) |
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+ | ** HAHB is given as three doses (for the hepatitis B component) |
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+ | ** The hepatitis A component contains a full dose of hepatitis A vaccine, so a HAHB series essentially contains an extra unnecessary dose of hepatitis A vaccine |
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+ | * In people with contraindications or who are expected to have suboptimal response to vaccination, consider using immunoglobulin as preexposure prophylaxis |
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+ | ** Groups include: |
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+ | *** Infants less than 6 months of age |
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+ | *** Immunocompromised people in whom the vaccine may not be as effective (though they should also still be vaccinated) |
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+ | *** Anaphylaxis after previous hepatitis A vaccination or component thereof |
||
+ | ** Adminitering just before travel can confer immunity for up to 6 months of travel |
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+ | ** Dose is IMIg (GamaSTAN) 0.02 mL/kg for 3 months of protection, or 0.06 mL/kg every 6 months |
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+ | *** CDC recommends a dose of IMIg (GamaSTAN S/D) 0.2 mL/kg q2mo due to decreases in hepatitis A IgG among donors |
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+ | |||
+ | === Post-Exposure Prophylaxis === |
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+ | |||
+ | * Post-exposure prophylaxis is indicated for susceptible contacts including: |
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+ | ** Household members and close contacts of people infected with hepatitis A |
||
+ | ** Contacts in group childcare centres and kindergartens |
||
+ | ** Co-workers and clients of infected food handlers |
||
+ | * Prophylaxis is with monovalent hepatitis A vaccine |
||
+ | * In people with contraindications or who are expected to have suboptimal response to vaccination, immunogloulin should be given |
||
+ | ** Groups include: |
||
+ | *** Infants less than 6 months of age |
||
+ | *** Immunocompromised people and people with liver disease, who should receive both vaccine and immunoglobulin |
||
+ | **** If they have received IVIg ≥400 mg/kg within the 3 weeks before exposure, then they do not require further immunoglobulin |
||
+ | *** Elderly susceptible adults age 60 years and older may also receive both |
||
+ | ** It should be given as soon as possible, and can be given until 14 days after last exposure |
||
+ | ** Dose is IMIg (GamaSTAN) 0.02 mL/kg body weight |
||
+ | *** CDC recommends a dose of IMIg (GamaSTAN S/D) 0.1 mL/kg body weight due to decreases in hepatitis A IgG among donors |
||
[[Category:Picornaviridae]] |
[[Category:Picornaviridae]] |
Revision as of 20:33, 17 September 2020
Background
Microbiology
- Non-enveloped RNA virus within the Picornavirus family
- Three genotypes, I through III
- Difficult to kill: needs higher temperatures and lower pH than other viruses, or bleach- or ammonium-based cleaners
Epidemiology
- Fecal-oral transmission with person-to-person spread (including sex)
- Can be transmitted by contaminated food and water, as well
- Most often linked to travel or to household contacts
Clinical Manifestations
- Incubation period is from 15 to 50 days, with an average of 28 days
Diagnosis
Serology
IgM | IgG | Interpretation |
---|---|---|
– | – | No recent infection (unless in the incubation period). No prior infection or vaccination. |
– | + | No infection. Prior infection or vaccination. |
? | + | Cannot rule out active infection. Prior infection or vaccination. |
+ | +/– | Acute or recent infection. IgM positive from 2 weeks until 3-12 months. IgG positive from 8-12 weeks and remains positive for lifetime. |
Prevention
Vaccination
- Vaccination is indicated for people at increased risk of acquiring hepatitis A, or at increased risk of severe disease
- Travellers to endemic countries
- People with chronic liver disease
- Men who have sex with men
- People who use recreational drugs
- People living in communities with outbreaks or endemic hepatitis A
- Close contacts of children adopted from endemic countires
- Military personnel and humanitarian relief workers
- People receiving repeated doses of plasma-derived clotting factors
- Laboratory workers studying hepatitis A
- Zookeepers, veterinarians, and researchers who interact with non-human primates
- Vaccination requires two doses spaced at least 6 months apart
- It provides immunity for decades, and possibly for life
- Often given combined with hepatitis B vaccine (HAHB)
- HAHB is given as three doses (for the hepatitis B component)
- The hepatitis A component contains a full dose of hepatitis A vaccine, so a HAHB series essentially contains an extra unnecessary dose of hepatitis A vaccine
- In people with contraindications or who are expected to have suboptimal response to vaccination, consider using immunoglobulin as preexposure prophylaxis
- Groups include:
- Infants less than 6 months of age
- Immunocompromised people in whom the vaccine may not be as effective (though they should also still be vaccinated)
- Anaphylaxis after previous hepatitis A vaccination or component thereof
- Adminitering just before travel can confer immunity for up to 6 months of travel
- Dose is IMIg (GamaSTAN) 0.02 mL/kg for 3 months of protection, or 0.06 mL/kg every 6 months
- CDC recommends a dose of IMIg (GamaSTAN S/D) 0.2 mL/kg q2mo due to decreases in hepatitis A IgG among donors
- Groups include:
Post-Exposure Prophylaxis
- Post-exposure prophylaxis is indicated for susceptible contacts including:
- Household members and close contacts of people infected with hepatitis A
- Contacts in group childcare centres and kindergartens
- Co-workers and clients of infected food handlers
- Prophylaxis is with monovalent hepatitis A vaccine
- In people with contraindications or who are expected to have suboptimal response to vaccination, immunogloulin should be given
- Groups include:
- Infants less than 6 months of age
- Immunocompromised people and people with liver disease, who should receive both vaccine and immunoglobulin
- If they have received IVIg ≥400 mg/kg within the 3 weeks before exposure, then they do not require further immunoglobulin
- Elderly susceptible adults age 60 years and older may also receive both
- It should be given as soon as possible, and can be given until 14 days after last exposure
- Dose is IMIg (GamaSTAN) 0.02 mL/kg body weight
- CDC recommends a dose of IMIg (GamaSTAN S/D) 0.1 mL/kg body weight due to decreases in hepatitis A IgG among donors
- Groups include:
References
- ^ J. T. Stapleton. Host Immune Response To Hepatitis A Virus. Journal of Infectious Diseases. 1995;171(Supplement 1):S9-S14. doi:10.1093/infdis/171.supplement_1.s9.