Intended for healthcare professionals

Education And Debate

Commentary: Antenatal screening and targeting should be sufficient in some countries

BMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7086.1036 (Published 05 April 1997) Cite this as: BMJ 1997;314:1036
  1. Philip P Mortimer, Director, Hepatitis and Retrovirus Laboratorya,
  2. Elizabeth Miller, Head, Immunisation Divisionb
  1. a Central Public Health Laboratory, London NW9 5HT
  2. b Communicable Disease Surveillance Centre, Public Health Laboratory Service, London
  1. Correspondence to: Dr Miller

    Introduction

    Van Damme and colleagues criticise some European countries for failing to integrate hepatitis B vaccine into national immunisation policies as recommended by WHO. But does their analysis really apply to countries which, like Britain, have hepatitis B virus carrier rates as low as 0.3%1 and report yearly incidences of acute infection of about 1/100 000?2 And is the inclusion of three doses of vaccine in infant schedules, or an attempt to deliver three doses to all adolescents, the most cost effective preventive approach for these countries? We doubt it and suggest that at present it would be preferable to concentrate on reinforcing existing strategies.

    The most important step is to stop maternal transmissions of hepatitis B virus, with their high risk of long term carriage developing in the newborn. Thus, in Britain the Departments of Health advise that “antenatal clinics should … consider offering [HBsAg] screening to all antenatal patients” and that neonates born to positive mothers should be fully immunised. Even if, as Van Damme et al suggest, there was a universal immunisation programme for infants, those born to women infected with hepatitis B would still have to be identified and immediately given hepatitis B immunoglobulin or vaccine, or both, at birth, with at least two further doses of vaccine. This intervention has been shown to prevent 90% of maternal transmissions and universal infant immunisation would merely be a supplement, not an alternative, to it.

    Unfortunately only a minority of pregnant women in Britain are currently screened for hepatitis B surface antigen despite government advice. Moreover, the proportion of infants thereby identified who complete the three dose vaccine schedule is disappointingly low. Infants to whom the Public Health Laboratory Service Communicable Disease Surveillance Centre issues hepatitis B virus immunoglobulin are all followed up, and reminders are sent to the paediatrician or general practitioner to ensure that the second and third doses of vaccine are given. Nevertheless, of 2514 infants followed up between 1987 and 1995, only 1633 (65%) received all three doses. Failure by the hospital to inform the general practitioner that second and third doses are required, poor understanding of the need for immunisation by parents (many of whom are immigrants with English language difficulties), and lack of an identified individual with local responsibility for the programme seem to be contributing factors. In Connecticut, United States, by contrast, completion of the three dose course has increased from 48% to 91% since dedicated nurses were appointed to implement the neonatal programme, and a computerised tracking system has been used to identify impending births to carrier mothers and the need for follow up doses of vaccine.4

    Full implementation of the rest of the existing British immunisation strategy would, by protecting more of those at identifiable risk, prevent many of the remaining virus transmissions. It should be actively promoted in clinics and in the primary care of groups at risk and by counselling known carriers and immunising their contacts. Those known to have antibody to hepatitis C virus who lack markers for hepatitis B virus should also be immunised.5 Admittedly, it is not easy to deliver full courses of vaccine,6 but there has been partial success. The falling incidence of reported acute hepatitis B infections in England, Wales, and Scotland over the past 10 years2 7 can be attributed to the vaccination policy as well as to changes in sexual behaviour and intravenous drug abuse.

    Global strategy is inappropriate

    Countries with a low incidence or prevalence of hepatitis B should therefore not be bound by a global strategy that, for them, is inappropriate. Two recent studies in Britain have examined the likely cost effectiveness of universal immunisation, though both suffer from a lack of accurate information about the age specific incidence of infection and the proportion of overt to cryptic infection. These uncertainties have led to substantially different cost benefit calculations. Mangtani et al suggested that supplementing the existing selective strategy by universal infant or adolescent immunisation would improve cost effectiveness,8 but Fenn and colleagues remain sceptical.9 The assumptions that only 10% of carriers in the Britain arise through perinatal transmission8 and that the laboratory confirmed acute hepatitis B cases reported to the Communicable Disease Surveillance Centre represent only 10% of all infections9 certainly need to be supported by fuller seroepidemiological studies.

    Results from adolescents born in England and Wales before neonatal immunisation against hepatitis B virus was generally available showed a surface antigen carriage rate of 0.15%, consistent with what would be expected from perinatal acquisition.10 A universal infant immunisation programme would therefore add little to the reduction in carriage rates in children achieved by a selective programme for high risk infants. A more definitive cost benefit analysis of universal immunisation, at least in England and Wales, must, however, await the results of the seroepidemiological study in adults. When this analysis is done it should take account of the difficulties of delivering a full course of the three dose vaccine, the likely long term protective efficacy of the course, and its possible impact on the continued acceptability of the whole immunisation programme.11

    Right or wrong, Van Damme et al's criticisms do draw attention to the proposition that it is time not merely to immunise against hepatitis B virus but to seek to eliminate it. In Britain we envisage a phased approach towards this goal: firstly, detect and protect all babies born to infected mothers and redouble efforts to immunise fully those who have identifiable risk of exposure; then, if new surveillance data indicate a clear need for it or when a more attractive vaccine formulation becomes available, immunise adolescents or possibly infants. For example, a strategy for adolescents would be much easier to implement if a single dose vaccine were available, and its cost effectiveness might be substantially improved by use of a combined hepatitis A and B vaccine.

    Our current reservations about universal immunisation should certainly not be taken to imply that prevention of hepatitis B is not a priority and that the halfhearted implementation of the preventive strategy already in place is therefore acceptable. With determination and a properly funded implementation strategy both acute hepatitis B infection and new carrier states could be virtually eliminated in Britain within the next decade.

    References

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    View Abstract