Rubella virus genotypes in the People's Republic of China between 1979 and 2007: a shift in endemic viruses during the 2001 Rubella Epidemic.

The incidence of rubella cases in China from 1991 to 2007 was reviewed, and the nucleotide sequences from 123 rubella viruses collected during 1999 to 2007 and 4 viral sequences previously reported from 1979 to 1984 were phylogenetically analyzed. Rubella vaccination was not included in national immunization programs in China before 2007. Changes in endemic viruses were compared with incidences of rubella epidemics. The results showed that rubella epidemics occur approximately every 6 to 8 years (1993/1994, 2001, and 2007), and a shift of disease burden to susceptible young adults was observed. The Chinese rubella virus sequences were categorized into 5 of the 13 rubella virus genotypes, 1a, 1E, 1F, 2A, and 2B; cocirculations of these different genotypes were found in China. In Anhui province, a shift in the predominant genotype from 1F and 2B to 1E coincided with the 2001 rubella epidemic. This shift may have occurred throughout China during 2001 to 2007. This study investigated the genotype distribution of rubella viruses in China over a 28-year period to establish an important genetic baseline in China during its prevaccination era.