As far as I know, measles is usually a more serious disease than chickenpox. The latter does not threaten death to the same degree maladies like loss of hearing and blindness. But chickenpox is very unpleasant while you suffer from it, there sometimes are very serious complications, and – most important – later in life there may be shingles, which aside from being very painful sometimes leads to terrible complications. (For instance, a friend’s otherwise very healthy mother, in her 60’s, had shingles which spread to her eyes and then her brain, leaving her brain-damaged after the shingles had cleared up.) Of course, there is a vaccine that helps protect against shingles, but – well, for these people it’s just another vaccine to reject.
Btw, there’s also mumps. Not usually as bad as measles or chickenpox at the time, but not fun. According to the Cleveland Clinic, “Rarely, mumps can affect your organs, including your brain, pancreas, testicles or ovaries. This usually only occurs in adolescents and adults…” (Testicles: infertility.) And there’s also rubella (“German measles,”), usually a mild disease, but it can, rarely, have serious complications. Rubella is definitely a serious disease for pregnant women since the complications for the fetus are not rare. The Mayo Clinic:
However, if you’re pregnant when you get rubella, the effect on your unborn child may be severe, and in some cases, fatal. Up to 90% of infants born to mothers who had rubella during the first 12 weeks of pregnancy develop congenital rubella syndrome. This syndrome can cause one or more problems, including:
** Growth delays*
** Cataracts*
** Deafness*
** Problems with the development of the heart (congenital heart defects)*
** Problems with the development of other organs*
** Problems with mental development and learning*
The highest risk to the fetus is during the first trimester, but exposure later in pregnancy also is dangerous.