rarer

"Most research has been conducted in cohorts with too few individuals thus lacking statistical power to uncover the rarer associations," he said.

"Because everyone gets measles these rarer effects actually end up being quite common."

It can also spread through a rodent's bite or scratch, but it is rarer.

But there are also rarer cases where domestic abuse killings are staged as suicide.

High-profile official events to mark the occasion may become rarer as time goes on, but she insists that it's a date that must continue to be acknowledged.