Contamination by Hepatitis C in a Haemodialysis Center: Preventive Measures

Dr. José Guiserix, Service de Néphrologie-Dialyse, BP 350 Chai, F-97448 Saint-Pierre, La Réunion (France) Dear Sir, In the haemodialysed population, hepatitis C has a particularly high [1], but very variable prevalence, ranging from 4% [2] to more than 56% [3] depending on the centre. Initially, the most obvious cause has been transmission through blood transfusions, as a result of the usual way of contamination by this virus and of the wide use of blood products in dialysis. This was notably the case in the earliest patients treated before synthetic erythropoietin was available, and before the carrying of hepatitis C was detectable among donors. Many works analysing seropositivity rates in different centres have since underlined that transmission is not only due to transfusion [3-5], but that other ways of contamination need to be considered [6, 7] as well as modalities of protection [8-10]. Physicians concerned about sparing their dialysed patients and their families [11] from contracting the disease when they come in to get treated, are now being faced with the question of the immediate setting up of simple and cost-effective preventive measures. The nephrology community still has in mind the ravages caused by hepatitis B before the availability of the vaccine, and might logically think about reintroducing the simple measures which had made it possible to contain the endemic at the time. Common sense prompts one to believe that measures suitable to limit the dissemination of the hepatitis B virus, are also likely to be effective in the case of hepatitis C [4]. The step from firstto second-generation hepatitis C tests had caused us, and others [12], an actual trauma. Sensitivity of the ELISA 2 tests had become excessive for diagnosis, as established retrospectively by the third-generation tests. This gave us the impression that in 6 months the seropositivity rate has increased by almost 50%, rising from 7 (11.7%) to 10 (16.7%) patients [13]. While carrying out the usual systematic measures, disinfection of the dialysate delivery systems with 48% chlorinated water and decontamination of the surfaces (mattress and dialysate delivery systems), we isolated se-ronegative patients in a room of their own [2, 14]. Seropositive patients were then treated exclusively on single-pass dialysate delivery (nonrecirculating) systems identified as being solely used for these patients. Later, the availability of the third test generation made it possible to analyse the phenomenon from a distance. In our centre, which has an average capacity of 60 haemodialysed patients, only one patient has had an actual true seroconversion (i.e. ELISA 1 to ELISA 3), between 1990 and 1995, rate 1/240 a year. Conversely, he had been dialysed during the interval in other centres, and kept up his sexual life but we have not been able to check his sexual partners [15]. Over almost a year, none of the falsely positive (ELISA 1 negative, ELISA 2 positive, not confirmed in ELISA 3) patients have been contaminated when dialysing as proved seropositive subjects.