Definition of "Mers"

Coronaviruses have been causing problems for humanity for a long time. Several versions are known to trigger common colds and more recently two types have set off outbreaks of deadly illnesses: severe acute respiratory syndrome (Sars) and Middle East respiratory syndrome (Mers).

2020 April 19, Robin McKie, “Coronavirus: five months on, what scientists know about Covid-19”, in The Guardian‎