The US Centers for Disease Control and Prevention has described the highly contagious delta variant of the first coronavirus detected in India as “worrisome”. CDC stated that the virus types found in the US are B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma), B.1.427 (epsilon), B.1.429. (epsilon) and B.1.617.2 (delta) are ‘variants of concern’. Earlier, the CDC had said about the delta form that more research is needed to be conducted over it. The World Health Organization (WHO) had described the delta variant as a variant of concern on May 10. According to the CDC’s estimate, as of June 5, delta variant was the cause of 9.9% of the cases of infection in the US.