A highly contagious COVID-19 variant first detected in southeast England may be present in Hawaii, state health officials said Tuesday.

Test specimens from four people in Hawaii contained a molecular signal associated with the U.K. variant. State laboratory technicians are conducting extra analysis of the virus’s genetic information to confirm by Friday whether it is the U.K. strain, according to Edward Desmond, the administrator of the Department of Health State Laboratories Division.

“It’s cause for concern, but not panic,”  said Dr. Sarah Kemble, the acting state epidemiologist. “This searching proactively for it will help us get a head start.”

As the virus mutates, many variants of COVID-19 have emerged, but health experts are primarily concerned with ones from the U.K., South Africa and Brazil due to their greater transmissibility. The South Africa variant shows signs of reducing the effectiveness of vaccines.

Kemble described it as a race between virus and vaccine.

“The concern is if you have something more contagious or easily spread, then that affects how many people you actually need to vaccinate in order to reach herd immunity, meaning we need to have a certain proportion of the population vaccinated to see that disease transmission slow or even stop in its tracks,” she said. Before the variants arose, the herd immunity target was about 60-70%, she said, but if the more contagious variants become dominant, that figure might rise to 80-90%.

Hawaii scientists have also detected a variant associated with California outbreaks among seven patients on Oahu, one on Maui and one on Kauai.

The California variant has not yet been proven to be more transmissible than other dominant strains. But it has likely been circulating in Hawaii for as many as five to six weeks, health officials said, noting that three of the patients recently traveled to California and one traveled to Utah.

The state lab division has been collecting 75 samples per week from patients across all islands as well as patients who recently traveled out of state.

Early studies show the variant that was first detected in southeast England may be 30% to 70% more transmissible than the current dominant strain, the Associated Press reported.

In late January, the U.K.’s chief scientist said the variant may carry a higher risk of death, but more research is needed.

Kemble said officials do not yet know if the Hawaii patients whose tests showed evidence of the U.K. strain had traveled out of state. If they had not, that could indicate that the variant is circulating in the community.