Enhanced contact investigations for nine early travel-related cases of SARS-CoV-2 in the United States. - Burke RM; Balter S; Barnes E; Barry V; Bartlett K; Beer KD; Benowitz I; Biggs HM; Bruce H; Bryant-Genevier J; Cates J; Chatham-Stephens K; et al. (PloS one, 2020)