COLUMBIA, South Carolina (AP) — A new coronavirus variant identified in South Africa has been found in the United States for the first time, with two cases diagnosed in South Carolina, state health officials said yesterday.

The two cases were discovered in adults in different regions of the state and do not appear to be connected. Neither of the people infected has travelled recently, the South Carolina Department of Health and Environmental Control (DHEC) said.

“That’s frightening,” because it means there could be more undetected cases within the state, said Dr Krutika Kuppalli, an infectious diseases physician at the Medical University of South Carolina in Charleston. “It’s probably more widespread.”

The arrival of the variant shows that “the fight against this deadly virus is far from over”, Dr Brannon Traxler, interim public health director at the DHEC, said in a statement.

“While more COVID-19 vaccines are on the way, supplies are still limited. Every one of us must recommit to the fight by recognising that we are all on the front lines now. We are all in this together.”

Viruses are constantly mutating, and coronavirus variants are circulating around the globe, but scientists are primarily concerned with the emergence of three. Other variants first reported in the United Kingdom and Brazil were previously confirmed in the US. Researchers believe these three variants may spread more easily.

As the variants bring a potential for greater infection risks in the US, pandemic-weary lawmakers in several states are pushing back against mask mandates, business closures and other protective restrictions ordered by governors.

In South Carolina, the state health agency said the variant was found in one person from the state’s coastal region and another in its north-eastern corner. The state gave no other information, citing privacy concerns.

Scientists last week reported preliminary signs that some of the recent mutations may modestly curb the effectiveness of two vaccines, although they stressed that the shots still protect against the disease. There are also signs that some of the new mutations may undermine tests for the virus and reduce the effectiveness of certain treatments.

The coronavirus has already sickened millions and killed roughly 430,000 people in the United States.