TY - JOUR
T1 - Mumps outbreak in the Republic of Moldova, 2007-2008
AU - Schwarz, Norbert G.
AU - Bernard, Helen
AU - Melnic, Anatolie
AU - Bucov, Victoria
AU - Caterinciuc, Natalia
AU - An Der Heiden, Matthias
AU - Andrews, Nick
AU - Pebody, Richard
AU - Aidyralieva, Chinara
AU - Hahné, Susan
PY - 2010/8
Y1 - 2010/8
N2 - Background: Moldova experienced a nationwide mumps outbreak between 2007 and 2008. Single-dose monovalent mumps vaccination at 15 to 18 months was introduced in 1983, replaced by a 2-dose MMR schedule at age 1 and 6 to 7 years in 2002. We investigated the outbreak to quantify its extent, explore the role of primary and secondary vaccine failure, and provide control recommendations. Methods: We analyzed national mumps surveillance and vaccination coverage data to estimate vaccine effectiveness (VE) using the screening method. A retrospective cohort study in 5 educational institutions was conducted to determine age-specific attack rates (ARs) and VE. We compared vaccine strain-specific ARs. Isolation and genotyping of mumps virus strains were performed. Results: Of 31,142 cases reported during October 2007 and July 2008, 80% were in 15-to 24-year-olds. Of cases with information (66%), 92% were vaccinated once, 4% twice. One-dose mumps VE estimates based on surveillance data over 1997-2001 declined from 91% (95% CI: 88%-92%) in 2-year-olds to 72% (70%-74%) in 15-to 19-year-olds. In the cohort study (n = 1589), VE was-40% (-120% to 20%) for 1 dose. For 2 doses it was 62% (-43% to 90%) in 13-to 15-year-olds. ARs were higher in individuals vaccinated with Urabe strains (43%) than with Leningrad-Zagreb strains (14%, P < 0.001). Mumps virus genotype G5 was identified. Conclusions: Low effectiveness of single-dose mumps vaccination was the main cause of the outbreak. Waning immunity may have contributed to this. The risk of mumps in 2-dose vaccinees was low. Other countries in which large population groups have received <2 doses of mumps vaccine may face similar outbreaks.
AB - Background: Moldova experienced a nationwide mumps outbreak between 2007 and 2008. Single-dose monovalent mumps vaccination at 15 to 18 months was introduced in 1983, replaced by a 2-dose MMR schedule at age 1 and 6 to 7 years in 2002. We investigated the outbreak to quantify its extent, explore the role of primary and secondary vaccine failure, and provide control recommendations. Methods: We analyzed national mumps surveillance and vaccination coverage data to estimate vaccine effectiveness (VE) using the screening method. A retrospective cohort study in 5 educational institutions was conducted to determine age-specific attack rates (ARs) and VE. We compared vaccine strain-specific ARs. Isolation and genotyping of mumps virus strains were performed. Results: Of 31,142 cases reported during October 2007 and July 2008, 80% were in 15-to 24-year-olds. Of cases with information (66%), 92% were vaccinated once, 4% twice. One-dose mumps VE estimates based on surveillance data over 1997-2001 declined from 91% (95% CI: 88%-92%) in 2-year-olds to 72% (70%-74%) in 15-to 19-year-olds. In the cohort study (n = 1589), VE was-40% (-120% to 20%) for 1 dose. For 2 doses it was 62% (-43% to 90%) in 13-to 15-year-olds. ARs were higher in individuals vaccinated with Urabe strains (43%) than with Leningrad-Zagreb strains (14%, P < 0.001). Mumps virus genotype G5 was identified. Conclusions: Low effectiveness of single-dose mumps vaccination was the main cause of the outbreak. Waning immunity may have contributed to this. The risk of mumps in 2-dose vaccinees was low. Other countries in which large population groups have received <2 doses of mumps vaccine may face similar outbreaks.
KW - disease outbreak
KW - measles-mumps-rubella vaccine
KW - mumps
KW - mumps vaccine
KW - vaccine effectiveness
KW - vaccine failure
UR - http://www.scopus.com/inward/record.url?scp=77955175063&partnerID=8YFLogxK
U2 - 10.1097/INF.0b013e3181d743df
DO - 10.1097/INF.0b013e3181d743df
M3 - Article
C2 - 20308934
AN - SCOPUS:77955175063
SN - 0891-3668
VL - 29
SP - 703
EP - 706
JO - Pediatric Infectious Disease Journal
JF - Pediatric Infectious Disease Journal
IS - 8
ER -