BMJ 1998;316:1317 ( 25 April )
Letters

New combined hepatitis A and B vaccine

Risks of viral hepatitis related to travel

EDITOR---The prevention of infectious diseases in travellers is an important public health measure which receives insufficient emphasis. Although Dedicoat and Ellis mention the importance of preventing the transmission of bloodborne viruses for which no vaccines are currently available,1 there are effective vaccines against viral hepatitis.

Around 1.4 million cases of hepatitis A are reported annually, with 350 million carriers of hepatitis B worldwide. Steffen reported the incidence of infection with hepatitis A in unprotected travellers as 3-6 per 1000 travellers per month of travel in a tourist resort, rising to 20 per 1000 per month for those in other settings.2 The incidence of hepatitis B was reported as 8-240 per 100 000 per month for ex-patriates, which fell by 2-10 times in short term travellers.2

The sexual transmission of hepatitis B is well recognised. Recent evidence suggests that advice about safe sex is often ignored by British tourists. One study showed that only 46% of young travellers having sex with a new partner used a condom.3 Other risk factors include exposure to unsterilised medical or dental instruments; use of unscreened blood during medical intervention such as after an accident (the commonest cause of death in travellers); and use of unsterilised equipment used in acupuncture, tattooing, and body piercing (all popular with visitors to developing countries).

British residents made 40 million visits abroad in 1995, an increasing proportion travelling to Africa, Asia, and Latin America. The increasing incidence of viral hepatitis related to travel is worrying. In one region of the United Kingdom travellers accounted for 6% of all reported cases of hepatitis B in 1981, for 8% in 1986, and for l2% in 1990-4.4

Travellers should receive advice and appropriate immunisations well in advance of travelling. Accelerated schedules of administration of combined hepatitis A and B vaccine (Twinrix) are currently being evaluated, which may result in more rapid protection against both hepatitis A and B for those travelling frequently and at short notice.

The use of multivalent vaccines has considerable advantages, including increased compliance and convenience, as well as providing concurrent protection. Monovalent vaccines would be recommended in some circumstances. However, for travellers exposed to a risk of viral hepatitis dual protection may be realised by the use of a bivalent hepatitis A and B vaccine, thus reducing the burden of infectious disease in this group.

Jane N Zuckerman, Head. 
Academic Unit of Travel Medicine and Vaccines, Royal Free Hospital School of Medicine, London NW3 2PF

  1. Dedicoat M, Ellis C. New combined hepatitis A and B vaccine. BMJ l 997;315:951. ( 11 October.)

  2. Steffen R. Hepatitis A and B: risks compared with other vaccine-preventable disease and immunisations. Vaccine 1993; 11: 518-520[Medline].

  3. Ford N, Wiser JR. Risk and liminality. The HIV-related socio-sexual interaction of young tourists. In: Clift S, Page S, eds. Health and the international tourist.. , London: Routledge, 1996:152-179.

  4. Boxall E. Universal childhood or adolescent vaccination: consideration. In: Zuckerman AJ, ed. Prevention of hepatitis B in the newborn, children and adolescents. , London: Royal College of Physicians, 1996:99-105.

Immunisation is only part of preventing infectious disease

EDITOR---Dedicoat and Ellis suggest restricting the use of the new combined hepatitis A and B vaccine (Twinrix) because the number of travellers returning infected with these hepatitides is not such to warrant active immunisation.1

The task of preventing infectious disease falls on primary care. Immunisation is only a part of this care. The main thrust of prevention is advice on how to stay healthy abroad. If patients don't come to us for their vaccinations what chance do we have in giving them important advice on how to stay healthy abroad?

Combined and monovalent vaccines exist that can prevent the two most frequently occurring immunisable diseases among travellers---namely, hepatitis A and hepatitis B. Hepatitis B vaccine is a means of preventing a sexually transmitted disease, which is also a severe disease with hepatic sequelae, including primary liver carcinoma. An estimated 850 000 deaths annually worldwide are due to hepatitis B related liver cancer. Eighty per cent of all liver cancers are due to hepatitis B virus, which is second only to tobacco as a worldwide carcinogen.

In the United Kingdom the provision of clean water for drinking and washing, modern sewage disposal systems, and greatly increased standards of personal hygiene have reduced the prevalence of hepatitis A. Immunity to the virus is falling, leaving a growing number of susceptible people. Children no longer contract the disease in their early years, when it is mainly asymptomatic, and they are in danger of catching the disease as adults, when sequelae can be considerable.

General practitioners and practice nurses are left with the responsibility of ensuring the best advice is given to travellers. Avoiding infection is the most effective prevention. Vaccination provides a good second line of protection.

Which traveller should, therefore, be immunised against hepatitis A and B? My advice is:  

  • Short term travellers staying for a month or more

  • Long term travellers

  • Frequent travellers

  • Ex-patriate workers

  • Travellers coming in contact with local people---for example, immigrant children visiting their homeland

  • Occupational groups such as aid workers, missionaries, healthcare workers, and military and diplomatic staff

  • People with risky lifestyles: intravenous drug users, adventurous people risking injury, homosexuals, and men and women with multiple sex partners or whose sexual behaviour is likely to place them at risk

  • Chronically ill travellers with underlying health problems that may necessitate seeking medical care abroad.2

George Kassianos, General medical practitioner. 
Bracknell, Berkshire RG12 7WW

  1. Dedicoat M, Ellis C. New combined hepatitis A and B vaccine. BMJ 1997; 315: 951[Full Text]. (11 October.)

  2. Kassianos G. Immunization, childhood and travel health. , 3rd ed. Oxford: Blackwell Healthcare Communications , 1997.

New vaccine is an adjunct, not an alternative to preventive behaviours

EDITOR---Dedicoat and Ellis argue that the use of vaccines should be evidence based,1 which is our policy at SmithKline Beecham Pharmaceuticals. Hepatitis A and B are the most frequently occurring immunisable diseases in travellers, threatening more people than typhoid and cholera combined.2 Therefore, Twinrix, the world's first combined hepatitis A and B vaccine, is a logical choice for travellers who may be at risk of both infections. Contrary to what Dedicoat and Ellis say, the vaccine is not promoted in the lay press. Also, the duration of travel is not disregarded.

Duration of travel is becoming less important when prescribing travel vaccines, particularly hepatitis B vaccine, as people's destinations become more exotic and their behaviours more risky---for example, adventure holidays with the risk of accidents and the attendant risk of parenteral treatments.3 Furthermore, people's sexual behaviour on holiday is also changing.3-5 The Department of Health guidelines cited by Dedicoat and Ellis do not suggest reserving hepatitis B vaccine for travellers spending more than one month in highly endemic areas, and they also recommend that short term tourists who place themselves at risk through their sexual behaviour should protect themselves from hepatitis B when abroad. Duration of travel is even less important for the risk of hepatitis A in areas of medium to high endemicity as the risk exists as soon as a traveller arrives in the area.

Awareness of the risks of injections and adherence to safe sexual practices are important in preventing transmission of hepatitis B virus, as well as HIV and hepatitis C virus, for which no vaccines are currently available. Vaccination provides an opportunity for healthcare workers to reinforce this message, as well as providing the available vaccine protection. Twinrix has not been promoted as an alternative to practising safe sex or cautioning against receiving unsterile medical treatment abroad but as an adjunct to good travel health advice. Such advice not only covers safe sex and advice about sterile needles but also includes safety messages about avoiding insect bites, complying with malaria prophylaxis, and hygienic food and water preparation.

Awareness of Twinrix has served to increase awareness of the risks posed by visiting regions where standards of hygiene and sanitation are not optimal. As a responsible vaccine provider, SmithKline Beecham supports vaccination as an adjunct to the overall health care for travellers, not as an alternative to preventive behaviours.

Karl Birthistle, Assistant director, clinical research and development/medical affairs. 
Alastair Benbow, Medical director. 
Smithkline Beecham Pharmaceuticals, Welwyn Garden City, Hertfordshire AL7 1EY

  1. Dedicoat M, Ellis C. New combined hepatitis A and B vaccine. BMJ 1997; 315: 951[Full Text]. (11 October.)

  2. Steffen R. Risk of hepatitis A in travellers. Vaccine 1992; 10(suppl 1): S69-S72[Medline].

  3. Keystone J. Hepatitis A and B---the risks to travellers. Proceedings report: Joining forces to conquer hepatitis A and B. London: Royal College of Physicians , 1996.

  4. Gillies P. HIV-related risk behaviours in UK holiday makers. AIDS 1992; 6: 339-340[Medline].

  5. Ford N, Erser R. Risk and liminality. The HIV related socio-sexual interaction of young tourists. In: Clift S, Page S, eds. Health and the international tourist. , London: Routledge, 1996:152-179.

 

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