Information
Editors
MaijaLappalainen
MarttiFärkkilä
HennaRautiainen
Viral Hepatitis
Essentials
- Hepatitis A and E can be best prevented by adequate food and drinking water hygiene, particularly in high-risk countries.
- Hepatitis B and C can be prevented by exercising due care in high risk occupations and in sexual behaviour. The single most important risk factor for hepatitis C is IV drug abuse.
- Prophylaxis against hepatitis A by vaccination is indicated before travelling to high-risk countries.
- Hepatitis B vaccination is indicated in high-risk occupations Vaccines for Preventing Hepatitis B in Health-Care Workers and for risk groups
- (N.B.: Vaccination recommendations in this article are based on Finnish guidelines.)
Basic principles of diagnosis
- Recent hepatitis A, B or E infection is demonstrated by the following tests: total anti-HAV antibodies (if positive, anti-HAV IgM), hepatitis B surface antigen (HBsAg), IgM antibodies to hepatitis B core antigen (anti-HBc IgM) and IgM antibodies to hepatitis E virus (anti-HEV IgM).
- Distinguishing a fresh hepatitis C infection from an old one cannot be done by serology. Active hepatitis C can be detected by testing for HCV nucleic acid (qualitative method) in addition to anti-hepatitis C virus antibodies.
- If clinically mild hepatitis is associated with symptoms suggestive of mononucleosis (fever, lymphadenopathy, splenomegaly, upper respiratory tract symptoms) or evident cholestasis (increased plasma ALP and bilirubin concentrations), possible mononucleosis can in the early stage be detected by a rapid test, and if needed, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) antibodies can be determined.
Hepatitis A
Route of infection
- Usually faecal-oral route, but epidemics have also occurred among users of illicit intravenous drugs.
Clinical picture
- Acute onset
- Loss of appetite and nausea are the initial symptoms.
- Fever
- Jaundice
Laboratory tests
- Plasma ALT and AST are increased.
- A specific diagnosis can be made by determining serum anti-HAV IgM.
- Total antibodies can be determined to assess the need for prophylaxis. A positive test result for total antibodies (and a negative result for IgM antibodies) is indicative of an earlier infection or a successful HAV vaccination that protects against the disease.
- See picture 1.
- Avoidance of susceptible foods (especially mussels and other sea food) when travelling in high-risk countries
- Hepatitis A vaccinationHepatitis A Immunisation in Persons Not Previously Exposed to Hepatitis A is particularly indicated for those who stay a long time in, or travel frequently to, high-risk countries should be vaccinated. A booster vaccination 6-12 months after the first dose is recommended. Current knowledge does not support giving further boosters to immunocompetent persons after the 2-dose program. Travellers should be vaccinated at least 2 weeks before the travel.
- For children aged 16 or over and for adults, two doses (Havrix® 1440 ELISA-U/ml, 1 ml or Avaxim® 0.5 ml) of vaccine are given at months 0 and 6-12.
- In children aged 1-15 years, Havrix® at half the adult dose (0.5 ml) is used.
- Hepatitis A+B combination vaccine Twinrix®
- Given in three doses at months 0, 1 and 6.
- A separate vaccine is available for children below 16 years of age.
- Hepatitis A vaccination is always recommended for tourists travelling to the tropics and to the African and Middle Eastern coasts of the Mediterranean. For the Baltic countries, Russia and Eastern European countries vaccination is recommended if the intended stay is of a long duration or repeated visits are anticipated.
- If an exposure to hepatitis A virus occurs, the exposed persons are protected primarily by vaccinating. The vaccine should be given no later than 2 weeks after the exposure.
Contagiousness
- One week after the onset of jaundice the virus is no longer excreted in the faeces.
- No permanent carrier status has been identified.
Course of the disease and follow-up
- The disease is self-limiting, and no specific treatment is available.
- Fulminant hepatitis is a rare complication of the infection and develops in about 0.3% of those infected.
- Prolonged icterus (cholestatic hepatitis A) may complicate the disease in adults.
- Extrahepatic symptoms include arthritis, vasculitis and cryoglobulinaemia.
- The severity of liver damage is estimated by the determination of plasma albumin concentration and prothrombin time. The disease is mild if prothrombin time does not fall below 0.40 and plasma albumin concentration does not fall below 30 g/l.
- Plasma ALT concentrations should be monitored weekly until they start to decline.
Hepatitis B
Route of infection
- Parenteral (syringes used in IV drug abuse, blood products)
- Sexual contact
- Perinatal transmission
Clinical picture
- Similar to that in hepatitis A, but the onset is often slower.
- About 1% of those infected will develop acute fulminant hepatitis, associated with 80% mortality rate without liver transplantation.
- Joint symptoms in 10-20% of patients
- Skin symptoms
- Liver aminotransferase concentrations rise more slowly than in hepatitis A.
Laboratory diagnosis
- Increased plasma AST and ALT
- A specific diagnosis is made by determining serum HBsAg and anti-HBc IgM.
- For the assessment of infectivity, the primary investigation is the determination of hepatitis B e-antigen (HBeAg). If the result is positive, the patient is likely to have active hepatitis and the disease is much more infectious as the virus is actively replicating. The most exact estimation of viraemia is achieved by quantitative determination of HBV-DNA. This should be used particularly if the HbeAg-negative form of chronic HBV infection is suspected.
- See table T1 and picture 2.
Interpretation of hepatitis B serology
| HBsAg | HBsAb | HBcAb | HBcAbM | HBeAg | HBeAb |
---|
Non-infected | - | - | - | | | |
Vaccinated | - | + | - | | | |
Natural immunity | - | +1) | + | | | |
Acute infection |
| +2) | - | - | - | +/- | |
| + | - | + | +++ | + | |
Carrier |
| + | + | + | +/-3) | +4) | - |
| + | - | + | - | - | + |