498
OBJECTIVES : Recently published studies have demonstrated increased efficacy and cost - effectiveness of combination therapy with interferon and alpha - 2b / ribavirin compared with interferon - alpha monotherapy in the treatment of chronic hepatitis C ( CHC ) .
 Chemical: ribavirin; Chemical: interferon - alpha; Disease: chronic hepatitis C; Disease: CHC
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: ribavirin; Chemical: interferon - alpha; Disease: chronic hepatitis C; Disease: CHC