AFRO	WHO African Region
AMRO	WHO Region of the Americas
CINAHL	Cumulative Index to Nursing and Allied Health Literature
EIA	Enzyme immunoassay
ELISA	Enzyme-linked immunosorbent assay
EMRO	WHO Eastern Mediterranean Region
EPI	Expanded Programme on Immunization
GMC	Geometric mean concentration
GMT	Geometric mean titre
GRADE	Grading of Recommendations Assessment, Development and Evaluation
HIV	Human immunodeficiency virus
IgG	Immunoglobulin G
IgM	Immunoglobulin M
IU/mL	International units per millilitre
JBI	Joanna Briggs Institute
LMICs	Low- and middle-income countries
MBA	Multiplex bead assay
MCV	Measles-containing vaccine
MCV1	First dose of measles-containing vaccine
MCV2	Second dose of measles-containing vaccine
MEDLINE	Medical Literature Analysis and Retrieval System Online
mIU/mL	Milli-international units per millilitre
MMR	Measles–mumps–rubella vaccine
MMR2	Second dose of measles–mumps–rubella vaccine
MR	Measles–rubella vaccine
MR1	First dose of measles–rubella vaccine
MR2	Second dose of measles–rubella vaccine
NR	Not reported
PICO	Population, intervention or exposure, comparator, and outcome
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses
PRNT	Plaque reduction neutralization test
PROSPERO	International Prospective Register of Systematic Reviews
R0	Basic reproduction number
RCT	Randomized controlled trial
RoB	Risk of bias
SEARO	WHO South-East Asia Region
SIA	Supplementary immunization activity
SIAs	Supplementary immunization activities
WHO	World Health Organization