Sorry, it's a 1 in 7 risk of meningitis. I got muddled up. It's pancreatitis that carries the 1 in 20 risk.
For anyone who missed it, here are the statistics on complications associated with catching mumps.
Around 1 in 7 children - male and female - who contract mumps will develop viral meningitis.
1 in 20 develop pancreatitis.
1 in 20 experience temporary hearing loss, for some this will develop into permanent hearing loss.
1 in 20 females who contract mumps will have swelling of the ovaries, it's as painful as it sounds.
1 in 1000 develop encephalitis, a life threatening complication.
It's is not a mild disease.