Hepatitis A is more common in countries outside Northern and Western Europe, North America, Australia and New Zealand
Travel abroad is a common factor in sporadic cases in the UK
- highest risk areas for UK travellers are the Indian subcontinent and the Far East, but the risk extends to Eastern Europe
- are two products for immunisation against hepatitis A
- an immunoglobulin provides rapid but temporary immunity
- vaccine confers active immunity but response is not immediate
- vaccines are available as either monovalent, or combined with either typhoid or hepatitis B
- Hepatitis A monovalent vaccines and those combined with either typhoid or hepatitis B do not contain thiomersal - vaccines are inactivated, do not contain live organisms and cannot cause the diseases against which they protect
- monovalent vaccines
- currently there are four monovalent inactivated hepatitis A vaccines (which can be used interchangeably)
- seroprotective levels of neutralising antibody may not be detected for 12-15 days following administration (2)
- gives protection for at least one year.
- if a patient is staying abroad for long periods or likely to travel repeatedly then a booster dose (usually given 6-12 months later - the exact time varies with product) will give protection for beyond 10 years
- combined vaccination (hepatitis A + B or hepatitis A + typhoid)
- may be used when protection against both diseases are required
Human normal immunoglobulin
- Human normal immunoglobulin (HNIG) is prepared from pooled plasma derived from blood donations
- use of HNIG should be limited to situations where it may have a definite advantage over vaccine
- HNIG can provide immediate protection, although antibody levels are lower than those eventually produced by hepatitis A vaccine
- because of a theoretical risk of transmission of vCJD from plasma products, HNIG used in the UK is now prepared from plasma sourced from outside the UK, and supplies are scarce
Reinforcing immunisation
- a booster dose of hepatitis A vaccine should be given at six to 12 months after the initial dose - results in a substantial increase in the antibody titre and will give immunity beyond ten years, however, effective protection beyond ten years cannot be assured until this booster is given
- until further evidence is available on persistence of protective immunity, a further booster at 25 years is indicated for those at ongoing risk
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