VHPB consensus statement on the safety of hepatitis B vaccines. (December 1998)
Source : Geneva Report (see publications)
- The group reached the following consensus:
- Epidemiological studies have identified that transmission of hepatitis B virus occurs through contact with contaminated blood and other clinical materials, sexual transmission, child to child transmission and through household contacts. Yet in almost all countries studied, approximately 1/3 of hepatitis cases occurs in people who are not included in these identified high risk groups. Strategies that target only groups at high risk of hepatitis B virus infection have failed, therefore strategies that protect the population at large are encouraged.
- Those who have already been vaccinated should be reassured that no studies demonstrate that they are at increased risk of developing MS.
- MS does not occur in children <1 year of age. There is no reason to believe that infant immunisation with hepatitis B vaccine will change this fact.
- MS is a very rare disease in children and adolescents. Amongst the cases of MS that have been reported to surveillance systems, there is no evidence that MS was caused by the hepatitis B vaccine in these cases.
- By better understanding the pathogenesis and aetiology of MS and related demyelinating disorders one would be in a position to identify factors that influence its initiation and outcome. Therefore, research into the causation and immunopathogenesis of CNS demyelinating disorders including MS should be encouraged and supported.
- Similarly, the influence of HB vaccination on immune functions, including immunological memory, should be further investigated. An important aspect of immunological research concerns the availability of biological material including T and B lymphocytes, monocytes, serum and plasma which has been stored properly. Therefore a close collaboration between epidemiologists and clinical researchers is essential. This also implies close liaison with regulatory authorities.
- Any future or ongoing study of demyelinating disorder and HB vaccine should take advantage of the large experience gathered to date on conducting MS aetiologic studies and the Guidelines developed. The vaccine and MS communities would benefit from jointly organising the best possible case-control study on aetiology of MS. Such a study would examine a wide range of hypotheses (though each being as specific as possible); including different viral, bacterial and parasital infections, environmental factors, and vaccinations, and control for various potential confounders.
- Principal investigators of existing studies should standardise methodology to facilitate future meta-analysis. In addition, validation of vaccination exposure should be improved by obtaining a copy of the vaccination certificate and/or serology for hepatitis B surface antibody. Researchers should also collect better information on potential confounders.
- The creation of an European Union vaccine pharmacovigilance and vaccine safety studies network would improve signal generation and hypothesis testing.
- The data available to date, although limited, does not demonstrate a causal association between HB immunisation and CNS demyelinating diseases, including MS. No evidence presented at this meeting indicates a need to change public health policies with respect to HB immunisation. Therefore, based on demonstrated important benefits - including the prevention of cirrhosis and cancer, and a hypothetical risk, the group supports the WHO recommendations that all countries should have universal infant and/or adolescent immunisation programs and continue to immunise adults at increased risk of HB infection as appropriate.
