Mpox cases raise concerns

These are not the first U.S. cases of what is known as clade I mpox. But all six previous cases were among international travellers who were believed to have been infected abroad.

Both infected people in California were hospitalized, and they are now recovering at home. Officials declined to give other details. But "at this point in our investigations, we have not identified any association between the two cases," Long Beach health department acting public affairs officer Jennifer Ann Gonzalez said.

Long Beach is located in Los Angeles County but has its own city health department. Investigators there say they have not found a close contact who traveled abroad, nor have they confirmed additional cases. A few of the person's close contacts have been given a vaccine, said Nora Balanji, the Long Beach department's communicable disease coordinator.

"We don't have any proof that there has been ongoing community transmission," she said. "It's something we're looking into. That's something we're concerned about."

A newer form of the clade I virus has been widely transmitted in eastern and central Africa. The World Health Organization declared the situation a public health emergency, but last month it said the problem had waned enough that it was no longer an international emergency.

Still, "it's concerning if this virus has come here and now is starting to be transmitted from person to person," said William Schaffner, MD, an infectious diseases expert at Vanderbilt University.