Characterization of rubella virus genotypes among pregnant women in northern Vietnam, 2011-2013.

Rubella virus (RV) infection is an unresolved clinical complication that affects children in developing countries including Vietnam. RV infection during the first trimester of pregnancy causes severe birth defects known as congenital rubella syndrome. This study reports on the genomic characterization of RV strains circulating in northern Vietnam during 2011-2013. RV-IgM positive amniotic fluid specimens were collected from 38 women from northern Vietnam who presented with clinical rubella at the National Hospital of Obstetrics and Gynecology in Hanoi, Vietnam. The RV genes were determined by nested PCR with primers amplifying the 739-nucleotide coding region of the E1 gene. The sequences from the amplified DNA fragments were phylogenetically analyzed and compared to reference RV strains. Seventeen out of 38 samples are positive for RV detecting. All new RV isolates are clustered to genotype 2B. Eighteen amino acid mutations were found in the T and B cell epitopes. These results suggest that genotype 2B RV strains frequently circulate in northern Vietnam. These data describe the RV genotype in Vietnam with the aim of improving maternal and child health in this country.