We found the B.1.617.2 (Delta) variant from May that reached highest in July (94.9%). The B.1.617.2 (Delta) variant of SARS-CoV-2 was identified in India in late 2020 and has subsequently been detected in approximately 60 countries, including the US.1 Our finding of the prevalence of Delta from more than three states indicates that Delta virus infection was widely spread in various regions of the USA in July. In fact, the CDC also declared at the end of July that B.1.617.2 (Delta) was responsible for more than 83% of COVID-19 cases that were reported in the US.22 It has L452R, T478K, and P681R substitutions in the S protein. The study identified that spike mutation P681R is a significant determinant for enhanced viral replication fitness of the Delta compared to the Alpha variant.23 The effect of the mutations L452R and T478K on ACE2 binding was also observed as enhanced stabilization of the RBD-ACE2 complex. Our result showing gradual decrease in cases of Alpha and increase in cases of Delta from June and July is consistent with a preprint posted in July, which explained that Delta is 40-60% more transmissible than Alpha and almost twice as transmissible as the original Wuhan strain of SARS-CoV-2.24 The same study added that viral loads in Delta infections were 1260 times higher than those in people infected with the original strain. The recent outbreak of B.1.617.2 (Delta) variant in the gymnastics facility of Oklahoma found the B.1.617.2 variant to be highly transmissible in indoor sports settings and within households.21 The finding emphasized multicomponent prevention strategies including vaccination to reduce the spread of SARS-CoV-2. It was estimated that hospitalization is twice as likely in unvaccinated individuals with Delta than in unvaccinated individuals with Alpha.25 Furthermore, due to only 48% of the total US population having been fully vaccinated, chances of increasing and spreading of SARS-CoV-2 is predominant.24 According to the CDC, in July 2021, within one week, the average increase in new COVID-19 cases and hospitalizations were 69.3% and 35%, respectively.26