translation.en: Due to a series of factors, a very low proportion of carriers (less than 1%) will eventually become ill. This most frequently occurs in young children, but a second disease peak is observed among adolescents and young adults.
translation.lv: Virkne faktoru var izraisīt ļoti mazas daļas (mazāk nekā 1%) slimības pārnēsātāju saslimšanu. Tas visbiežāk notiek maziem bērniem, bet otra riska grupa ir pusaudži un gados jauni pieaugušie.