title: Waning immunity to measles in young adults and booster effects of revaccination in secondary school students.
abstract: The increasing proportions of adult cases were observed in the recent measles outbreaks in Zhejiang Province, China. In order to identify the high-risk age groups of measles for targeted intervention, a seroprevalence survey of measles antibody was conducted among 1961 participants aged 0-60 years randomly selected by age-stratified purpose sampling, and the effect of revaccination program in secondary school was evaluated in Zhejiang Province. The adjusted overall seropositivity rate of measles was 88% (95% confidence interval [CI]: 86-89%) with geometric mean titers (GMT), 976±86 mIU/ml. The seropositivity rate of measles was significantly lower in subjects aged 15-19 years than aged 5-9 years (90% vs 96%, χ(2)=5.21, p=0.022). Both seropositivity rate and GMT level of measles were higher in participants aged 10-14 years with ≥2 doses MCV than those with only 1 dose (95% vs 81%, 1276 mIU/ml vs 666 mIU/ml). The seropositivity rate increased from 91% to 100% after revaccination with MCV among 184 secondary school students. The proportions of measles cases aged ≥15 years were reduced gradually (χ(2)=55.47, p=0.000) from 2009 to 2011 after implementing the revaccination campaign on secondary school students since 2008. Our findings strongly suggested that a revaccination opportunity with MCV for adolescents helps to improve the population immunity, and it can be conducted effectively and practically in secondary school students.
authors.affiliation: Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, PR China. hhqcdc@163.com
authors.forename: Hanqing
authors.initials: H
authors.lastname: He
authors.forename: En-fu
authors.initials: EF
authors.lastname: Chen
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Yan
authors.forename: Jian
authors.initials: J
authors.lastname: Fu
authors.forename: Jinren
authors.initials: J
authors.lastname: Pan
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002681:China; D005260:Female; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008457:Measles / Q000276:immunology* / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D008875:Middle Aged; D012574:Schools; D016036:Seroepidemiologic Studies; D013334:Students; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D008458:Measles Vaccine