Fig 1. Annual incidence, on logarithmic scale, of IMD in Italian Regions with <20% of annual cases with UNK serogroup by age group: A) <1, B) 1-to–4, C) 5-to–14, D) 15-to–24, E) ≥25 years.

p-values from Poisson univariate regression models with epidemiological year as covariate are in the right side.