A variant strain of the virus, known as B.1.617, is also circulating in India, along with other variant strains, including B.1.1.7, first detected in the United Kingdom, and B.1.351, first detected in the Republic of South Africa.
“The CDC advises, based on work by public health and scientific experts, that these variants have characteristics of concern, which may make them more easily transmitted and have the potential for reduced protection afforded by some vaccines,” said the proclamation.