Anticipating new coronavirus variants can slow the spread, health experts say

(CNN) - As 2023 starts, many health experts believe watching out for new coronavirus variants will be increasingly important to slow the spread of COVID-19 in the new year.

In the United States, omicron subvariants are still the cause of almost all COVID-19 infections.

While omicron spreads easily, data from the Centers for Disease Control and Prevention shows it causes less severe illness and fewer deaths than earlier variants.

”I hope it continues in that direction, but there’s no guarantee,” Dr. William Schaffner with Vanderbilt University Medical Center said.

The latest omicron subvariant now accounts for more than 40% of U.S. COVID-19 cases.

Offshoots continue to spread globally as well, especially in China after the country lifted the bulk of its COVID-19 restrictions.

The surge there has prompted the U.S. to require a negative COVID-19 test for all travelers from China beginning Jan. 5.

”The Chinese government is not sharing the genetic information about these viruses with the rest of the world,” Schaffner said.

Some health experts say that the travel requirement is important as new variants are likely to emerge in the future.

”Perhaps, worst case scenario, variants that could evade the protection of our current vaccines and therapeutics,” Schaffner said.

Others believe that the U.S. testing requirements for travelers will not prevent new COVID-19 cases from coming to the U.S. or new variants from emerging, but it may buy the U.S. some time.

”It’s something we can do to help protect the people of the United States,” Schaffner said.

While COVID-19 levels remain far below those of prior surges, trends are on the rise in parts of the U.S., and there is growing concern that case numbers could soar now that the winter holidays have passed.