This is an interesting slide. It shows rubella notifications in specified parts of the USA before (1966-68) and after (1975-77) the introduction of vaccination for rubella in the second year of life (in 1969).

It illustrates the expected increase in age at infection: in 1975-77, a larger proportion of cases were 15+ years (yellow numbers). Despite this, the age-specific incidence in persons aged 15+ years was lower in 1975-77 (red numbers) along with the total incidence which was also lower (bottom line).

This was a favourable outcome of immunisation: the (inevitable) relative increase of rubella occurrence in older age-groups was accompanied by an absolute decrease.

(Source of data: Preblud SR, Serdula MK, Frank JA, Brandling-Bennett AD, Hinman AR. Rubella vaccination in the United States: a ten-year review. Epidemiol Rev 1980; 2:171-94.)