Transfusion-transmitted
diseases
Hepatitis B virus infection, once a
serious problem in thalassaemics, is now very uncommon, due to the combined
efficacy of Ihe hepatitis B surface antigen screening in blood donors and the
implementation of vaccination.
The vast majority of the patients who are now more than 10 years old are
anti-HCV-positive from early childhood, as a consequence of the transmission
of HCV from infected blood donors before the introduction of anti-HCV
screening. In 1992, Ihe prevalence of confirmed second-generation anii-HCV
reactivity in a cohort of 1,481 Italian Ihalassaemics was 85% [8], with a
frequency of persistent viraemia of approximately 70% [D. Prati, un- published
data]. On liver biopsy, substantial fibrosis or cirrhosis are found in 15% of
adult viraemic patients [58]. Cryoglobufinaemia, an extrahepatic manifestation
of HCV infection, is present in 66% of thalassaemics, and seems lo be
particularly frequent in cirrhotic patients [59]. Even after the introduction
of anti-HCV screening, however, primary HCV infection remains an important
cause of morbidity among thalassaemics. The current incidence - 4.27
cases/1,000 person-years - is 40-fold higher than that observed among low-risk
adults from the same geographic area. This incidence translates into an
infection risk substantially different from that expected on the basis of the
incidence/window period model (I/ 7100 vs. 1/50,000 units) [8, 60], which seems
to indicate that a proportion of HCV cases currently occurring among
Ihalassaemics may not be related to blood transfusion, but may be acquired in
the community or through the nosocomial route (8).
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