From The Lancet Infectious Diseases:

Findings

Our calculations show that negative outcomes are 4·5 times worse for measles, 2·2 times worse for chickenpox, and 5·8 times worse for rubella than would be expected in a pre-vaccine era in which the average age at infection would have been lower.

https://www.sciencedirect.com/science/article/pii/S1473309915000535