The prevalence of hepatitis A antibodies among Israeli travellers and the economic feasibility of screening before vaccination.

BACKGROUND: Hepatitis A (HA) is the most common vaccine-preventable disease among travellers. The probability of contracting the disease depends on the endemicity in both the destination and country of origin of the traveller. The introduction of the new highly effective but expensive inactivated HA vaccine necessitates a re-evaluation of HA prevention policy. In highly developed countries all travellers require vaccination. In highly endemic areas the entire population is immune. In Israel, HA seroprevalence declined from 94% in the early 1970s to < 60% in the mid 1980s. Living in a country in which the HA endemicity is changing, we studied the current situation of HA seroprevalence among travellers and the cost-benefit of screening for HA IgG before vaccination.

METHODS: Israeli travellers of all ages, (range 22-74 years) expecting to spend a considerable time abroad presented to the travel clinic for pre travel advice and vaccination. A brief medical history was taken, including history of jaundice. Blood for HA IgG testing was drawn.

RESULTS: In the present study, 389 Israeli travellers were screened for HA IgG. Overall, 46% were seropositive: 26% in the 21-30 group (n = 102); 37% in the 31-40 group (n = 145); 62% in the 41-50 group (n = 62); and 79% in the > 50 group (n = 80).

CONCLUSIONS: In countries where hepatitis A endemicity is changing, an evaluation of seroprevalence and then a cost benefit calculation should be made. In Israel, assuming a current cost of $130 for vaccination and $30 for the IgG test, it is economically valid to screen Israeli travellers > 30 years old for HAV IgG before vaccination. A formula is presented for calculating the cost benefit ratio in any country, based on local endemicity according to age group.