Australia’s Queensland state has found a new omicron lineage in a traveler who arrived from South Africa, health authorities said Wednesday, writes Fortune.com.

The new lineage has about half the gene variations of the original and can’t be detected with typical screening, the state’s acting chief health officer Peter Aitken told reporters. It was found in a traveler who had arrived from South Africa and tested positive for the coronavirus on Saturday, he said.

The new lineage has enough markers “to be able to classify it as omicron, but we don’t know enough about it as to what that means then as far as clinical severity, vaccine effectiveness”, - Aitken said. “We now have omicron and omicron-like”.

The discovery comes as Queensland prepares to finally reopen its border to the rest of Australia ahead of schedule next Monday, as more than 80% of the eligible population will be fully vaccinated later this week.

The discovery may be a setback for scientists racing to understand the full impact of the omicron variant, including how virulent the strain is and whether vaccines are effective at reducing risk of severe disease. Although most genetic changes are innocuous as viruses mutate, some can make the mutant more adept at infecting cells, for example, or evading antibodies.