Molecular epidemiology of rubella during the pre- and post-elimination eras in the Americas

Since the last case of indigenous rubella virus (RuV) was detected in 2009 in the Region of the Americas, sporadic rubella and congenital rubella cases have been confirmed, and subsequently, a low number of associated sequences have been reported. Fifty-one sequences of wild-type RuV, representing four genotypes (1E, 1G, 1J, and 2B), were reported from five countries, with confirmed sources of exposure for 46 cases. Phylogenetic analysis revealed the diversity of these viruses, showing no associations with sustained endemic transmission from previously endemic strains. Notably, 13 sequences were associated with travel from countries where no genetic information of wild-type viruses was available. In addition to sequences from postnatal and congenital infections, 23 sequences were collected from patients with diseases associated with RuV persistent infection. These findings highlight the Region's success in maintaining rubella elimination, emphasize its valuable contribution to global RuV molecular epidemiology, and address potential challenges in progressing toward the goal of rubella eradication.