Not all travellers need immunoglobulin for hepatitis A.

Viral hepatitis A occurs endemically in most parts of the world, especially where there is overcrowding,' and studies on the prevalence of antibody to hepatitis A in Europe have shown higher concentrations among those who live in Mediterranean countries.2-6 It is an infection often associated with travel: in West Germany and Switzerland over 60% of acute cases have a history of recent travel abroad,7 and in the west of Scotland 20% ofcases are in returning travellers.8 The beneficial effect of human normal immunoglobulin in preventing hepatitis A has long been recognised,9 and it is commonly given to intending travellers to countries where there might be increased exposure to hepatitis A.'° The dramatic upsurge in the number of people travelling from Britain-22-1 million visits abroad were made by British citizens in 1984, 12% to destinations beyond Europe"-has increased the need to protect travellers from hepatitis A. Do all such travellers need immunoglobulin? A random serum survey of 511 travellers predominantly from the west of Scotland conducted between 1979 and 1983 showed that 64% already had antibodies to hepatitis A-30% of those aged 10-19 rising to 89% of those over 60 (personal observations). This is similar to the prevalence reported in random testing of blood donors in 1980 from the same area and in comparable age groupings.'2 Thus many intending travellers already possess antibody and are presumably not at risk from hepatitis A. Added to this is the question of expense. An injection of normal immunoglobulin costs £3-£9 depending on the manufacturer and dose (250 mg intramuscularly for six weeks' protection and 750 mg for six months' protection'3); and in certain circumstances a fee of£3.45 may be claimed by doctors from the health board.'4 Last year the West of Scotland Blood Transfusion Service distributed 1249 phials, most to immunise prospective travellers (Scottish National Blood Transfusion Service, personal communication). When this cost is balanced against that of antibody testing (from £8 down to £4 depending on laboratory throughput (Hepatitis Reference Laboratory, Glasgow, personal communication) there is a distinct economic benefit in selective screening before immunising as opposed to immunising the putative traveller at risk. Using such information, Larouze et al have devised a formula that enables the cost benefit to be calculated.'5 This benefit accrues with increasing age in the traveller, length of stay abroad, and frequency of visits abroad; implementing a screening policy also minimises unnecessary immunisation and makes for effective use of a limited resource. JONATHAN H COSSAR Research associate DANIEL REID Consultant epidemiologist Communicable Diseases (Scotland) Unit, Ruchill Hospital, Glasgow GlO 9NB