WASHINGTON - The United States has contributed "very little" to the global effort of finding and tracking new versions of COVID-19 like Omicron, the Associate Press has reported.

"With uncoordinated and scattershot testing, the US was sequencing fewer than 1 percent of positive specimens earlier this year. Now, it is running those tests on 5 percent to 10 percent of samples," said the report published Tuesday.

At present, more than 20 countries are sequencing a larger proportion of positive specimens than the United States, the report noted.

"I think we still have a long way to go," the report quoted William Moss, professor at the Johns Hopkins Bloomberg School of Public Health, as saying.

The report noted that many experts believe Omicron has probably already made its way into the United States, and that the variant "will be picked up by the surveillance system soon."

However, the United States does not "have the sorts of interstate travel restrictions that would make it possible to contain the virus in any one place," the report quoted David O'Connor, professor of the Department of Pathology and Laboratory Medicine at the University of Wisconsin-Madison, as saying.