The U.S. Centers for Disease Control and Prevention said on July 5 that 70.1% of the new confirmed cases of new crowns in the United States in the week ended on the 2nd were caused by the mutant strains of Omicron BA.4 and BA.5 subtypes.
According to Reuters, citing data from the US Centers for Disease Control and Prevention, among the confirmed cases in the United States, the cases caused by BA.4 and BA.5 accounted for 16.5% and 53.6%, respectively.
The two new subtypes accounted for more than 50% of cases in the week ended June 25, compared with just 1% in early May.
"U.S. News and World Report" reported on the 5th of this month that in the past month and a half, there have been an average of about 100,000 new confirmed cases of new crowns in the United States per day. The proportion of fast and asymptomatic infections is high, and many people believe that the real number may be much higher than this.
The data also shows that in the week ended on the 2nd, among the confirmed cases in the United States, the proportion of cases caused by subtypes BA.2.12.1 and BA.2 of the previously major epidemic strains Omicron dropped to about 27% and 3%, respectively. %.
Some experts believe that Omicron BA.4 and BA.5 subtypes have a stronger ability to "escape" vaccine protection or immunity from infection, but booster shots can still greatly reduce the severity and mortality of the new crown.
The U.S. Food and Drug Administration recommended last week that Covid-19 vaccine manufacturers change the design of booster shots to better deal with the two new subtypes of Omicron.