MMR	Morbilli-Mumps-Rubella
HCW	Healthcare workers
IgG	Immunoglobulin G
GMC	Geometric Mean Concentration
WHO	World Health Organisation
CRS	Congenital Rubella Syndrome
SAGE	Strategic Advisory Group of Experts
EU/EEA	European Union and European Economic Area
MM	Morbilli-Mumps
ECDC	European Centre for Disease Prevention and Control
AP	Autonomous Province
ELISA	Enzyme linked immunosorbent assay