elimination as a public health problem

The World Health Organization uses three different words for three different achievements, and they are easy to run together. Eradication means a disease is gone worldwide and permanently. Elimination in the sense of interrupting transmission means it is no longer spreading within a particular country. Elimination as a public health problem is a third and lower bar: the disease still exists, but it has been pushed below an agreed level at which it no longer causes significant harm across a population.

There is no single number that applies to every disease. The threshold is set disease by disease, and a country has to show both that it has met that specific target and that it can keep meeting it. When WHO validated Australia's elimination of trachoma as a public health problem, the definition rested on a stated prevalence of trachomatous trichiasis, a measurable figure for that disease rather than a general rule.

This matters for reading the news. A country that has eliminated a disease as a public health problem has done something real, verified by WHO against a published target. It has not eradicated the disease. Surveillance continues, individual cases can still occur, and in principle the status can be lost again if the numbers climb.