Experts in the U.S. have warned that the loosened restrictions and new COVID-19 variants could complicate the fight against the pandemic despite the country's increasing vaccination rate, CNN reported. 

"What Texas, Mississippi, other states are doing to relax and get rid of the mask orders and kind of act like everything is back to normal, that is definitely coming down on the side of the variants," said Ashish Jha, dean of the Brown University School of Public Health. 

There are at least a dozen states including Texas and Mississippi that have eased restrictions this month as the vaccination rate in the U.S has climbed, boosting hopes for a kind of normality in the U.S.  

Texas is the largest U.S. state to lift its mask mandate. Other states to drop the masks are Michigan, Louisiana and Mississippi.

In Mississippi, the move has already started to manifest its drawbacks. According to Johns Hopkins University data, the number of new cases has spiked by 19 percent from last week with an average of 463 new infections per day. 

In addition, new cases in 15 U.S. states jumped by 10 percent over the week. The figure stands at 40 percent for Minnesota and Michigan, according to the data. 

Experts also warned petering out of new cases needs more time as multiple variants are circulating in the country.