Dynamic Change in Variation of Rubella Viruses Circulating in Mainland China.

We wished to study the dynamic change in variation of rubella viruses circulating during 1999-2015 in mainland China at the molecular level. Molecular evolution of Chinese rubella viruses collected during 1999 ~ 2015 was analyzed according to a surveillance database of measles/rubella laboratory networks in China. A total of 1737 rubella viruses were obtained from 20 of 31 provinces (except Xinjiang and Tibet) during 1999 ~ 2015. Four genotypes (1E, IF, 2A, 2B) were detected. The genotype-1E rubella virus was detected first in 2001. Subsequently, genotype 1E became the predominant genotype circulating during 2001~2013, and could be divided into two closely related clusters (A (2004-2015) and B (2001-2009)). However, the detection rate of the genotype-1E rubella virus decreased year-by-year from 2011, and reached the lowest level (1. 3%) in 2015. The genotype-1F rubella virus was restricted geographically to China, and no longer found after 2002; presumably its circulation in China was interrupted. All genotype-2A rubella viruses were derived from vaccine-related cases. At least four genotypes of 2B rubella viruses (lineage 1 ~ 4) circulated in mainland China during 2000 ~ 2015. The genotype-2B rubella virus was detected sporadically and was in a weak position until 2010. However, the detection rate of imported genotype-2B rubella viruses (lineage 3) was increased and became the predominant genotype during 2014~2015. Through the study of 16 consecutive years in mainland China, the evolution and epidemic situation of the rubella virus was obtained to aid virology surveillance for rubella control in China.