Hepatitis risk and vaccination among Australian travellers overseas

To the Editor: Figures from the Australian Bureau of Statistics show that Australians make about 3.3 million overseas departures each year.1 Few data are published on the extent to which Australian travellers seek pre-travel health advice, what vaccinations they receive, and what risks they are exposed to during travel.

A series of surveys of travellers examining these questions has been conducted under the auspices of the Travel Health Advisory Group, a coalition of Australian travel and medical organisations. Surveys were conducted in 1996, 1997, 2000, 2001 and 2002. On each occasion, a market research company telephoned people from mainland capitals using numbers randomly selected from the telephone directory. This process continued until 500 people aged 18 or over who had travelled overseas in the previous two years had been interviewed. In the 2002 survey, about 10 000 calls were made to complete the interviews. The questions on vaccinations focused on hepatitis A and B, two of the most common vaccine-preventable diseases associated with travel.2

Results from the 2002 survey are shown in the Box. A minority of people (31%) reported seeing a doctor or travel clinic for pre-travel health advice. Of those who saw a doctor or travel clinic, 31% did so two weeks or less before departure.

Over the series of surveys, there has been an increase in travel to destinations with high- or intermediate-risk for hepatitis A infection, from 40% of travellers in 1996 to 58% in 2002. Despite this increase, only a minority of travellers could recall ever being vaccinated for this illness. Travellers were informed about how they might be exposed to hepatitis A and B and asked if they believed that they could have been at risk during their most recent overseas trip. Substantial numbers recalled a risk (34% and 16% for hepatitis A and B, respectively) and some of these could not recall being vaccinated (18% and 7%, respectively) (Box).

These surveys have methodological limitations, including lack of information on the consent rate and potential recall bias. However, the results suggest that substantial numbers of travellers do not seek pre-travel health advice and are at risk of vaccine-preventable diseases during travel. Not only does this have implications for individual travellers, it also creates public health risks, as travellers can introduce hepatitis A and B into their home communities. These results suggest more public education is needed about the importance of pre-travel health advice and appropriate vaccination.