In the United States, Delta, the Indian variant of Corona, sounded the alarm.
The US Centers for Disease Control (CDC) has instructed that masks be worn in offices and other public places despite being fully vaccinated.
The CDC said that those who have been vaccinated in the worst-affected areas should also wear masks after delta variant cases come to light.
On the other hand, experts have identified the reasons for the rapid spread of the Indian species Delta of Corona, which revealed that the Delta virus develops its own species very quickly, while the symptoms of Delta appear more than the previous type of virus. Time is very short.