Statistical analysis

Four sampling phases were established: 1994–2003, 2004–2008, 2009–2013, and 2014–2020. The most early (1994–2003) and recent (2014–2020) phases encompassed more years to account for the relatively fewer data available in these years. We compared categorical data with the x2 test and continuous data with one-way ANOVA, wherever appropriate. We analysed the variables for clustering using univariable and multivariable logistic regression. Variables considered were region, HCV subtype, population characteristics, and sampling phase. We analysed all variables separately and entered those associated (P<0.1) with the outcomes into the multivariable model. We present the results as odds ratios (ORs) with 95% confidence intervals (CIs). We performed all analyses using R (version 4.1.1; R Foundation, Vienna, Austria). We used listwise deletion to handle missing data.