Hepatitis A

Hepatitis A is a viral infection of the liver. It is mostly transmitted through contaminated food or water and is common in areas where water quality and environmental sanitation are poor.  Bad personal hygiene (not enough hand washing) may also contribute to transmission. It can also be transmitted through oral sex.

Most adults in low and low middle -income countries have already acquired the disease in childhood and are immune for life. They are usually unaware of exposure, as the disease can have no symptoms in young children. Older Australians and those who have migrated from less developed countries may also be immune due to exposure in childhood (90% under 6 years of age).  A blood test can check for natural immunity.     

The World Health Organisation (WHO) estimates there are more than 120 million cases of hepatitis A annually.  Sporadic outbreaks are common and sometimes prolonged. The mortality rate is low.

Hepatitis A is much less likely in high income countries with good public health infrastructure.                     

Travel related hepatitis A does occur. Owing to its long incubation period, travellers often become sick after returning home. Travel was responsible for about 46% of cases in the USA between 2005 and 2007 and for nearly 30% of cases in Europe between 2009 and 2015. 

Hepatitis A has always been considered the most important vaccine preventable disease apart from influenza. This is still the case despite considerable reductions in infection rates globally.  This has been observed even in Africa and is most likely due to better access to clean water and improvements in hygiene and sanitation.  Despite changes in risk, media reports of hepatitis A fatalities in travellers are often good reminders of disease impact.  It is hard NOT to recommend vaccination when the protection from a course is likely to be life or at least 25 years,

Hepatitis A is a notifiable disease in Australia and between 150 and 200 cases are reported annually. A substantial reduction in cases was observed after hepatitis A vaccination was included in the National Immunisation Program for Aboriginal and Torres Strait Islander children in 2005.

Travel was identified as a factor in 82% cases analysed in 2016. The top 4 countries included India, Pakistan, Iraq and Vanuatu.          

It doesn’t make sense for travellers to be unprotected, particularly when travelling to high-risk locations. Hepatitis A has a long convalescent period and the impact on work can be significant after returning home. There is no treatment to shorten the duration of the illness. The illness tends to be more severe in older people with some studies showing a 3% mortality in people over 40. It is mostly (90%) asymptomatic in children under 6 years of age. This can lead to outbreaks in childcare settings with significant disease in their carers.