Abstract | BACKGROUND: The rubella vaccine was introduced into the immunization program in 1995 in the Shandong province, China. A series of different rubella vaccination strategies were implemented at different stages of measles control in Shandong province. METHODOLOGY/PRINCIPAL FINDINGS: The average reported incidence rate of rubella cases remained at a low level in Shandong province after 1999. However, rubella epidemics occurred repeatedly in 2001/2002, 2006, and 2008/2009. The age of the onset of rubella cases gradually increased during 1999-2010, which showed that most cases were found among the 10 years old in 1999 and among the 17 years old in 2010. Phylogenetic analysis was performed and a phylogenetic tree was constructed based on the World Health Organization standard sequence window for rubella virus isolates. All rubella viruses isolated in Shandong province were divided into 4 genotypes: 1E, 1F, 2A, and 2B. Genotype 1E viruses accounted for the majority (79%) of all these viruses. The similarity of nucleotide and amino acid sequences among genotype 1E viruses was 98.2-100% and 99.1-100%, respectively. All Shandong genotype 1E strains, differed from international genotype 1E strains, belonged to cluster 1 and interdigitated with the viruses from other provinces in mainland China. The effective number of infections indicated by a bayesian skyline plot remained constant from 2001 to 2009. CONCLUSIONS/SIGNIFICANCE: The gradual shift of disease burden to an older age group occurred after a rubella-containing vaccine was introduced into the childhood immunization schedule in 1995 in Shandong province. Four genotypes, including 1E, 1F, 2A, and 2B, were found in Shandong province during 2000-2009. Genotype 1E, rather than genotype 1F, became the predominant genotype circulating in Shandong province from 2001. All Shandong genotype 1E viruses belong to the genotype 1E/cluster 1; they have constantly circulated, and co-evolved and co-circulated, with those from other provinces.
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Authors | Changyin Wang, Zhen Zhu, Qing Xu, Aiqiang Xu, Xueqiang Fang, Lizhi Song, Weixiu Li, Ping Xiong, Wenbo Xu |
Journal | PloS one
(PLoS One)
Vol. 7
Issue 7
Pg. e42013
( 2012)
ISSN: 1932-6203 [Electronic] United States |
PMID | 22911874
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Topics |
- Adolescent
- Adult
- Age Distribution
- Base Sequence
- Bayes Theorem
- Child
- China
(epidemiology)
- Epidemics
(statistics & numerical data)
- Genotype
- Health Surveys
(statistics & numerical data)
- Humans
- Phylogeny
- Rubella
(epidemiology, virology)
- Rubella virus
(genetics, isolation & purification)
- World Health Organization
- Young Adult
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