“…Perhaps owing to this, mumps outbreaks have occurred worldwide over the past decades, mainly in vaccinated adolescents and young adults. These outbreaks often occurred in close contact settings (schools, households, parties), and were mostly caused by genotypes that are different from the vaccine genotype [5, 6, 7, 8, 9, 10, 11, 12, 13]. For instance, the current vaccine used in the Netherlands contains the Jeryl-Lynn strain (genotype A), and is genetically distant from the recent outbreak strains (genotypes D and G) [14, 15].…”