Implementation of a hepatitis A prevention policy in haemophiliacs: results from the French cohort.

ABSTRACT

In the early nineties, the occurrence of hepatitis A outbreaks in some patients with haemophilia in some countries led French health authorities to recommend hepatitis A virus (HAV) vaccination in HAV-seronegative haemophiliacs. The French 'Suivi thérapeutique National des Hémophiles' cohort permitted to assess the implementation of this recommendation by the analysis of the vaccinal process, i.e. HAV seropositivity assessment and vaccination of HAV-seronegative patients, in a survival approach. In a subgroup of 812 patients diagnosed earlier than 1990 (prevalent cohort), the implementation of vaccinal process increased quickly from 0% in 1993 to 41.8% in 1994 and to 71.2% in 1996, suggesting a 'notification effect'. The vaccinal process was associated to three cofactors in a Cox model analysis (age, severity of haemophilia, centre of treatment). No infection was observed during the survey in this group. In another subgroup of 201 boys born since 1993 (incident cohort), 27.5% and 15.4% patients remained exposed to the risk at 3 and 5 years from diagnosis respectively, again with a 'centre effect', which might be linked to various factors such as regain in confidence for products or economic reasons. Only five infectious seroconversions were assessed over the 7-year survey, which represents 14.5 cases per 1000 person-year incidence without any relationship with products. Our data combined with the contemporary hepatitis A epidemiology and the current safety of anti-haemophilic concentrates, should lead to a new assessment of the risk of hepatitis A in haemophiliacs. We suggest that among patients with bleeding disorder, as well as in other populations, HAV prevention policy might be stressed on those who already suffer from chronic liver disease and/or travel in endemic countries.