S33

17. EXPECTED RETURN FROM ONGOING VACCINATIONS IN TERMS OF REDUCED

CANCER INCIDENCE.

tibrSssy L.. U.D.

Regional Officer for Cancer. Regional Office for Europe of

the WHO, Scherf igsvej 8, DK-2100 Copenhagen 0.

Today, the primary hepatocellular cancer of the liver is the only cancer that is preventable by immunization: evidence for an association between the carrier-state of hepatitis B infection and primary liver cancer is now sufficiently strong to justify the use of vaccine as a means of preventing this cancer. It has been demonstrated that the plasma-derived vaccine can reduce carrier state by 90%.

Primary liver cancer is among the ten most common cancers worldwide; it is estimated that there are at least 250 000 new cases each year (30 cases per 100 000). Aa a contrast, the actual incidence of the disease in Europe is less than five new cases per 100 000 population each year; the incidence rates greatly vary among the subregions of Europe, being lowest in Northern Europe and highest in the South. These incidence figures do not justify the embarkation of a widespread vaccination programme in Europe as public health measure against primary liver cancer.

Prevention of primary liver cancer might be a by-prouct of immunization against hepatitis B of high risk groups (i.e. health care personnel, selected groups of patients, contacts of patients with hepatitis B, infants born to HBsAg positive mothers, individuals whose lifestyle puts them at high risk of hepatitis B infection, etc.). Failure to immunize these people places them at unnecessary and unjustified risk.

In areas of high endemicity, where the dominant mode of HBV transmission is transmission from carrier mothers to their newborn children, universal immunization of all members as soon as possible after birth should be the aim.

Based on the previously described figures of prevalence and protective efficacy of vaccine, it seems likely, that - if all newborn children could be vaccinated in the highly endemic areas - nearly 200 000 cases of primary liver cancer would be avoided each year, which means 3% of the total cancer incidence worldwide.

At present, in addition to the need for infrastructure and personnel to deliver, the relatively high cost of vaccine is the main obstacle to embark on a widespread immunization programme by national health authorities in the majority of the countries concerned.

S34

The human papillomavirus (HPV 16.18) infection Is another significant public health problem for which development of a vaccine would have a great impact on cervical cancer Incidence; vaccine development has been at research stage.

References:

1. Parkin, D.M. et al: Estimates of the worldwide frequency of twelve major cancers. Bull. WHO 62: 163-182. 1984. -

2. Prevention of hepatocellular carcinoma by Bull. WHO 61: 731-744. 1983. -

3. Immunization against Hepatitis B: Report hepatitis in Europe. J. Med. Virology 17: -

immunization. A WHO meeting.

on a WHO meeting on Viral 209-217. 1985.

4. Muir C.S. et al: The world cancer burden: prevent or perish. British Medical Journal 290: 5-6. 1985. -

5. Genital Human Papillomavirus infections and cancer. Report on a WHO meeting. Unpublished document. WHO 1987.