Hepatitis A vaccination

Hepatitis A

The spread of hepatitis A is mainly by the faecal-oral route but also by person-to-person contact (although food and drink contamination may be involved). The infection can be silent, especially in children, and the hepatitis can be with or without jaundice. Fulminant hepatitis occurs in less than 0.4% of people and usually manifests during the first four weeks of illness.¹

See also the article on Hepatitis A.

Hepatitis A vaccine²

There are two products for immunisation against hepatitis A. An immunoglobulin provides rapid but temporary immunity. The 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 are inactivated, do not contain live organisms and cannot cause the diseases against which they protect. Three monovalent vaccines are currently available: Havrix®, Avaxim® and Vaqta®.

Combined hepatitis A and hepatitis B vaccines (Twinrix® and Ambirix®) contain purified inactivated hepatitis A virus and purified recombinant hepatitis B surface antigen.

Combined hepatitis A and typhoid vaccines contain purified inactivated hepatitis A virus and purified Vi capsular polysaccharide typhoid vaccine (ViATIM®).

Human normal immunoglobulin (HNIG)

HNIG is prepared from pooled plasma derived from blood donations. Use of HNIG should be limited to situations such as post-exposure prophylaxis in groups with increased risk of severe disease where it may have an additional benefit to vaccine.

HNIG can provide immediate protection, although antibody levels are lower than those eventually produced by hepatitis A vaccine. Protection lasts for 4-6 months.

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. All donors are screened for HIV, hepatitis B and C.

Administration²

Vaccines are routinely given intramuscularly into the upper arm or anterolateral thigh.

For individuals with a bleeding disorder, vaccines should be given by deep subcutaneous injection to reduce the risk of bleeding.

Other vaccines can be given at the same time but a different site should be used.

Schedule²

In order to provide long-term protection, the immunisation regimes for hepatitis A vaccine and for combined hepatitis A and typhoid vaccine consist of 2 doses, with the second dose 6 to 12 months after the first.

The standard schedule for the combined hepatitis A and hepatitis B vaccine depends on the product.

• For Twinrix® the schedule consists of 3 doses, the first on the elected date, the second one month later and the third six months after the first dose.

• For Ambirix® the schedule consists of 2 doses, the first administered on the elected date and the second between six and twelve months after the first dose.

An accelerated schedule of Twinrix® Adult at 0, 7 and 21 days may be used when early protection against hepatitis B is required (eg, for travellers departing within one month).

A booster dose is usually given 6–12 months after the initial dose of hepatitis A-containing vaccine, and ensures immunity beyond 10 years. However, successful boosting can occur even if the booster dose is delayed by several years. A further booster dose 25 years after full primary immunisation is only considered necessary if the risk of hepatitis A infection is still present.³

Indications for hepatitis A vaccination^{2 3}

Pre-exposure prophylaxis

Immunisation against hepatitis A is recommended for individuals at high risk of hepatitis A exposure, those with certain underlying medical conditions, and those at risk of complications:

• Laboratory staff who may be exposed to the virus.

• Staff and residents of homes for those with severe learning difficulties, or where personal hygiene among patients may be poor.

• Workers at risk of repeated exposure to untreated sewage.

• Individuals who work with primates.

• Patients with haemophilia being treated with plasma-derived clotting factors.

• Patients with severe liver disease regardless of the cause (consider for those with chronic hepatitis B or C infection and for patients with milder liver disease).

• Individuals travelling to or going to reside in areas of intermediate or high prevalence.

• Individuals who are at risk due to their sexual behaviour (such as men who have sex with men).

• Individuals who inject drugs.

Immunisation may be considered under certain circumstances for:

• Food packagers and handlers where a case or outbreak occurs; advice should be sought from the local Health Protection Team.

• Staff in day-care facilities where there is a community outbreak; advice should be sought from the local Health Protection Team.

• Healthcare workers.

Travel

Pre-exposure immunisation is recommended for individuals travelling to or going to reside in areas of high or intermediate prevalence. Immunisation should ideally be given 2 weeks prior to departure, but can be given up to the day of departure. The use of normal immunoglobulin for travel prophylaxis is not recommended. Care should also be taken to avoid hepatitis A exposure through food and water.

Further information on country-specific hepatitis A risk is available from the National Travel Health Network and Centre and Travax websites (see Further Reading below).

Post-exposure prophylaxis

Close contacts should be considered immune if they have a documented history of either a completed course of Hepatitis A vaccination within the past 10 years, or a single dose of monovalent vaccine within the past year, or if they have previously had laboratory-confirmed hepatitis A.

Post-exposure prophylaxis is not required for healthy close contacts aged under 1 year not attending childcare. Immunisation should be offered to all those who assist in the child's toileting to prevent tertiary infection.

For close contacts aged 2–12 months attending childcare, a dose of monovalent hepatitis A vaccine [unlicensed use] should be given within 14 days of exposure. If the child contact cannot be immunised, appropriate advice should be given on enhanced hygiene in the childcare setting. If enhanced hygiene standards cannot be met, the child should be excluded from childcare for 30 days. If exclusion of the child is not possible, all carers and children aged 2 months and above in the childcare setting should be immunised. In these cases, any child that goes on to require long-term protection against hepatitis A after their first birthday, should be given the full course of two doses.

For healthy close contacts aged 1–59 years, a single dose of monovalent hepatitis A vaccine is recommended within 14 days of exposure. To ensure long term protection, a second dose of the vaccine should be given after 6–12 months.

For close contacts who have chronic liver disease (including chronic hepatitis B or C infection), HIV infection (CD4 count below 200 cells per microlitre), are immunosuppressed, or are aged 60 years or over, normal immunoglobulin in addition to monovalent hepatitis A vaccine is recommended within 14 days of exposure (up to 28 days in those with chronic liver disease). To provide long term protection, a second dose of the vaccine should be given after 6–12 months.

In households with more than one close contact, all unvaccinated household contacts seen within 8 weeks of jaundice onset in the index case, should be given the monovalent hepatitis A vaccine to prevent tertiary spread within the household.

Outbreaks

Immunisation with monovalent hepatitis A vaccine provides a long duration of protection, and may be effective in prolonged outbreaks, such as those that may occur with foodborne, school and community outbreaks (including among Traveller and other nomadic populations, as well as homeless persons where opportunities exist to intervene, eg, outreach at shelters, hostels, encampments and Traveller sites), to interrupt onward transmission.

The management of outbreaks of hepatitis A infection with HNIG and/or hepatitis A vaccine should be discussed with the local Health Protection Team.

Contra-indications to hepatitis A vaccination²

• Previous anaphylactic reaction to hepatitis A vaccine.

• Previous anaphylactic reaction to components of the vaccine.

• These vaccines are not licensed for children under the age of 1 year. However, the risks of hepatitis A for children under 1 year of age are actually very low.

NB: there are very few people who cannot receive this vaccine. These vaccines may be given to pregnant women and those women who are breast-feeding. Individuals with immunosuppression and HIV infection can also be given hepatitis A-containing vaccines, although seroconversion rates and antibody titre may be lower and appear to be related to the individual’s CD4 count at the time of immunisation. Re-immunisation should be considered and specialist advice may be required.

Adverse effects²

• Local: mild, transient soreness and redness.

• General: fever, malaise, fatigue, headache, nausea and loss of appetite. However, these are not common.