Prevalence of HCV infection in a health area of Madrid (Spain): The first step towards microelimination.

OBJECTIVE: To estimate the prevalence of HCV infection in the general population of a health area through an intervention in Primary Care, differentiating between new diagnoses and infections previously diagnosed but not treated.
METHODS: Participants were selected through a risk assessment questionnaire, with all those who gave at least one affirmative answer and all those over 50 years of age undergoing a rapid test. Positive tests were confirmed in the lab by determination of anti-HCV antibodies by chemiluminescent microparticle immunoassay and determination of viraemia.
RESULTS: Of the 7,991 participants, 36.2% presented a positive HCV risk questionnaire. 4,717 tests were performed, finding an anti-HCV percentage of 0.65% in the screened population, with 0.46% of active infections. Among the individuals with a positive test result, 51.9% had a known prior diagnosis but had not received treatment, because they were not aware of it or were not linked to the health system, and 19.2% had a positive result for the first time. The prevalence of hidden infection was higher in men, those over 50 years of age and people from Eastern Europe.
CONCLUSION: We found a prevalence of active infections higher than recently described nationwide, and a higher percentage of newly diagnosed infections than recent similar studies in other areas. These differences justify the need to perform local assessments of the prevalence of HCV infection in each of the health areas where it is planned to implement and monitor a microelimination programme.