The hepatitis A virus is usually spread via exposure to contaminated food and water or direct contact with an infected person and can cause debilitating symptoms, although most people fully recover. However, very rarely, hepatitis A infection can cause acute liver failure (fulminant hepatitis), which is often fatal. The World Health Organization (WHO, 2023) estimates that in 2016, a total of 7134 people died from hepatitis A worldwide (accounting for 0.5% of global mortality due to viral hepatitis).
Hepatitis A is closely associated with unsafe water or food, inadequate sanitation, poor personal hygiene and oral–anal sex (WHO, 2023). Improved standards of living and hygiene have led to a marked fall in locally acquired hepatitis A infection in the UK, although behavioural risk factors can increase risk, and cases continue to be reported in returning travellers (UK Health Security Agency (UKHSA), 2024a).
Transmission
Infected people shed hepatitis A virus in their faeces and are most infectious 1–2 weeks before they get any clinical signs and symptoms, such as jaundice or raised liver enzymes (when virus concentration is greatest in the stool and blood). Viral excretion and risk of transmission reduce rapidly after liver dysfunction or symptoms appear, which is concurrent with the appearance of circulating hepatitis A virus antibodies. However, babies and children can shed virus for up to 6 months after they are infected (US Centers for Disease Control and Prevention (US CDC), 2023).
Hepatitis A virus is spread by (UKHSA, 2024b):
Symptoms
Symptoms usually develop 2–4 weeks after exposure to the virus. They include fever, tiredness, loss of appetite loss, diarrhoea, nausea, abdominal pain, dark-coloured urine and jaundice (WHO, 2023; UKHSA, 2024b).
Not every infected person will experience all these symptoms; children under 6 years of age do not usually have noticeable symptoms, with only 10% developing jaundice. Adults have symptoms more often than children, with severe disease and risk of fatality becoming higher in older age groups. Hepatitis A sometimes relapses, but this is normally followed by a full recovery (WHO, 2023).
There is no specific treatment for hepatitis A; symptoms are treated as they appear. Hospital admission is likely to be required for someone who becomes acutely unwell. In older people (60 years and above), this acute phase of the infection is when liver failure is a risk. Once someone has recovered from hepatitis A infection, they will be immune for the rest of their life (UKHSA, 2024b).
Epidemiology
Geographical distribution areas can be characterised as having high, intermediate or low levels of hepatitis A virus (US CDC, 2023):
However, infection does not always mean disease as young children do not usually experience any noticeable symptoms. Infection is common in low- and middle-income countries with lack of good sanitation and poor hygiene practices. Infection rates are low in high-income countries with good sanitation, universal access to clean water and high standards of hygiene.
Hepatitis A may be reported in high-income countries, adolescents and adults in high-risk groups, including people who inject drugs, men who have sex with men, people travelling to areas of high endemicity, and in isolated populations like secluded religious groups. In the US, large outbreaks have been reported in homeless people (WHO, 2023).
Hepatitis A risk for UK travellers
Hepatitis A is more common in countries outside Northern and Western Europe, North America, Australia and New Zealand (UKHSA, 2024a). There has been a downward trend in hepatitis A infection in the UK over the last 25 years, with the number of laboratory reports of hepatitis A in England and Wales falling from 1318 in 1997 to 274 in 2021. However, travel abroad is a common risk factor for sporadic cases in the UK. The UKHSA advises that highest risk areas for UK travellers are the Indian subcontinent, the Middle East, Africa and South-East Asia, but the risk now extends to Eastern Europe (UKHSA, 2024a).
Sexual transmission linked to international travel
In 2024, the UKHSA reported that, in recent decades, there have been a number of hepatitis A outbreaks among gay, bisexual and other men who have sex with men (GBMSM) in the UK (UKHSA, 2024a). These UK outbreaks are linked to similar outbreaks in GBMSM in a number of other European countries (European Centre for Disease Prevention and Control (ECDC), 2022). Multinational outbreaks of hepatitis A in GBMSM have also been reported internationally since 2016 and are also associated with European countries reporting ongoing hepatitis A virus transmission in GBMSM (US CDC, 2021; 2024). Transmission in these outbreaks appears to be via the faecal–oral route (UKHSA, 2024a).
‘Infection rates are low in high-income countries with good sanitation, universal access to clean water and high standards of hygiene’
Accessing information about hepatitis A risk countries and current UK vaccine recommendations
All UK travel health professionals (including doctors) prescribing travel vaccines must know how to access and make sure they are familiar with the appropriate, evidence-based UK national guidance. As with any other travel-related infection, hepatitis A endemicity and vaccine recommendations can change in response to epidemiological changes or specific outbreaks and advice for higher risk travellers or changes in epidemiology.
Specific hepatitis A vaccines may no longer be available in the UK and new products can be introduced. Travel health professionals must maintain their skills and knowledge in order to deliver a safe and effective service (Faculty of Travel Medicine of the Royal College of Physicians and Surgeons of Glasgow (FTM RCPSG), 2020). An integral component of this is ensuring they are familiar with UK NHS-funded resources like the National Travel Health Network and Centre (NaTHNaC) website, which includes country specific advice and vaccine recommendations: https://travelhealthpro.org.uk/countries.
All NaTHNaC hepatitis A destination advice and vaccine recommendations are consistent with current UKHSA guidance: https://travelhealthpro.org.uk/factsheet/11/country-specific-information-rationale.
TRAVAX is an NHS website providing travel health information for Scottish travel health professionals and travellers provided by the Travel and International Health Team of Public Health Scotland. Registration details are available here: https://www.travax.nhs.uk/about-travax.
‘Food, water and personal hygiene must be emphasised to all pregnant women travelling abroad, and inactivated (non-live vaccines) are not contraindicated in pregnancy’
Pre-travel hepatitis A risk assessment
Asking the traveller to complete a pre-travel checklist before a consultation is a useful tool that helps the prescriber ensure they are getting all the information they need. Ideally, this encourages the traveller to provide all their destination details, any behavioural risk factors for hepatitis A and a full medical history, including any medication. However, it is crucial to discuss the completed pre-travel assessment form with the traveller, as there may be questions that they did not fully understand or issues they prefer to discuss in person. NaTHNaC has a free, comprehensive, downloadable travel risk assessment form:
https://travelhealthpro.org.uk/factsheet/61/risk-assessment--risk-management-checklist.
Recommendations for hepatitis A vaccine must consider:
Travellers at greatest risk of hepatitis A exposure and infection include those going to areas with inadequate sanitation and limited access to clean water (US CDC, 2023).
Non-medical prescribers
In the UK, while doctors remain the biggest group of prescribers, non-medical independent and supplementary prescribers from a range of other health professions, including nurses and pharmacists, are increasingly involved in travel medicine prescribing. Nurse and pharmacist prescribers can prescribe all travel vaccines, provided travel medicine care is within their scope of practice (Royal College of Nursing (RCN), 2023).
UK rules state that non-medical health professionals can only do this once they have completed an approved education programme, and should take responsibility for their own competence. This includes delegating when appropriate, seeking support if required and using their acquired knowledge, skills and professional judgement appropriately (Royal Pharmaceutical Society (RPS), 2021).
This extension of prescribing responsibilities to other professional groups outside the medical profession is likely to continue in circumstances (such as travel medicine) where there is a clear patient benefit, and it is safe to do so (RCN, 2023).
To be able to prescribe medicines, including vaccines, UK registered nurses must have recorded their prescriber qualification on the Nursing and Midwifery Council (NMC) register (2023). The Royal Pharmaceutical Society provides specific guidance for UK pharmacist prescribers: https://www.rpharms.com/prescribing.
Non-medical prescribing helps improve care, as it increases flexibility and gives better access to medicines (RCN, 2014). This is particularly important for travellers, especially those who may have to travel last minute for work or due to family illness or bereavement, and who may not be able to arrange a GP appointment before travel.
Currently available UK hepatitis A vaccines
There are several hepatitis A vaccines licensed for use in the UK. All are inactivated and prepared from different strains of the hepatitis A virus (NICE, 2021; NaTHNaC, 2022):
There are also combined hepatitis A and B vaccines:
Hepatitis A vaccine schedule
A hepatitis A monovalent vaccine is given as two doses, 6–12 months apart. If the second dose is missed there is no need to restart the course. Give the second dose as soon as possible after the missed dose. Antibodies may not be detectable for 12–15 days following administration of monovalent hepatitis A vaccine. However, the vaccine may provide some protection before antibodies can be detected and vaccination up to the day of departure may be beneficial. Theoretically, immunity persists for more than 20 years after the second dose. A further booster dose is recommended at 25 years for people at ongoing risk of infection. The schedule for the combined hepatitis A and B vaccine varies between products:
For travellers, the first dose of hepatitis A single or combined vaccine should ideally be given at least 2 weeks before travelling, but can be given the day of departure (NICE, 2021).
Resources
Contraindications
Hepatitis A vaccine should not be given to people who have had (NICE, 2021; UKHSA, 2024a):
Specific guidance on the contraindications and precautions associated with all the currently licensed hepatitis A vaccines in the UK are available from the Electronic Medicines Compendium: https://www.medicines.org.uk/emc.
Phenylketonylurea
Some hepatitis A monovalent and combined vaccines contain phenylalanine in varying amounts: Avaxim (Adult and Junior), Havrix (Monodose and Junior Monodose). As phenylalanine builds up in people with phenylketonylurea, the individual (or their parent or carer) should be advised to take account of this amount when meal planning on the day of vaccination. The specific amount contained in each formulation may be found in the respective vaccine's data sheet (UKHSA, 2024a).
Records
As with any vaccine, a clear record must be kept in the traveller's medical record of any hepatitis A vaccine administered. The traveller must also be given a clear written record of their hepatitis A vaccine and any other vaccines given, and advised to inform their GP surgery. Travel health consultations must not take place in isolation without consideration of other travel-related risks and documenting information (RCN, 2023).
Pregnancy
The effect of hepatitis A infection in pregnancy could be significant for both mother and baby. While food, water and personal hygiene must be emphasised to all pregnant women travelling abroad, inactivated (non-live vaccines) are not contraindicated in pregnancy. After a careful risk assessment, if a pregnant traveller's risk of hepatitis A is considered high, a vaccine can be prescribed and should be offered (NaTHNaC, 2023). Travel consultations must also allow consideration of other destination specific hazards (FTM RCPSG, 2020). Pregnant women should be advised of any other risks relating to their travel plans, such as mosquito-spread illnesses like Zika at her destination. All pregnancy-appropriate travel advice must be given, and any other appropriate destination-specific vaccines should be offered.
Liver disease
People who already have long-term (chronic) liver disease have a greater risk of becoming very unwell if they catch hepatitis A virus. In the most severe cases, the liver can stop working. This is known as acute-on-chronic liver failure, although the chances of this happening are rare (British Liver Trust, 2024).
Although people with chronic liver disease are at no greater risk of acquiring hepatitis A, due to the risk of hepatitis A infection causing severe illness in anyone with a serious liver condition, vaccination is recommended. Hepatitis A vaccine should also be considered for individuals with chronic hepatitis B or C infection and for anyone with milder forms of liver disease (UKHSA, 2024b).
Conclusion
In the UK, all currently available hepatitis A vaccines are safe, well tolerated and suitable for most travellers, including those with pre-existing liver conditions. Health professionals involved in hepatitis A travel risk assessment and vaccine prescribing should also consider individual behavioural risk factors, as well as hepatitis A endemicity at the traveller's planned destination.
Prescribers must be aware that certain groups of travellers, such as GBMSM, may be at increased risk of hepatitis A infection, regardless of their planned destination. These travellers will also need advice on how to protect themselves from other non-vaccine preventable infections, such as shigella, that can be passed on through via faecal–oral contact during sex (UKHSA, 2023).