Hospital-based surveillance suggested a high frequency of congenital rubella syndrome and the presence of genetically diverse genotype 2B rubella virus strains in Ethiopia

Abstract Objectives This study aimed to investigate the burden of Congenital Rubella Syndrome (CRS) and to provide baseline genotype data for monitoring future rubella control efforts in Ethiopia. Methods Between 2022 and 2023, active surveillance for CRS was conducted among infants at selected public hospitals in Addis Ababa. Demographic and clinical data, blood and respiratory samples were collected. Serum samples were tested for rubella-specific IgM and IgG antibodies by enzyme-linked immunosorbent assay. Viral RNA was extracted from nasopharyngeal and oropharyngeal swabs and subjected to rubella virus detection and genotyping RT-PCRs. Results Overall, 44 infants with suspected CRS were identified and the parents/guardians of 32 of them consented to participate. Among the 10 children with laboratory-confirmed CRS, congenital heart defects and eye abnormalities were the most common clinical manifestations. In seven IgM positive infants, rubella virus RNA was detected. The obtained sequences belonged to genotype 2B and clustered in three well-supported groups. Conclusions This study showed that nearly one third of the suspected CRS cases had laboratory evidence of rubella infection, confirming the high burden of CRS in the country. It also provided first information on rubella virus genotypes involved in CRS in Ethiopia for monitoring future control efforts.