Originally Published: 26 MAY 22 12:39 ET

Updated: 26 MAY 22 15:50 ET

By Betsy Klein and Jacqueline Howard, CNN

(CNN) -- The US Centers for Diseases Control and Prevention is investigating more cases of monkeypox across the United States as part of a global outbreak.

The CDC has identified nine monkeypox cases in seven states as of Wednesday, Director Dr. Rochelle Walensky said Thursday.

Cases have been identified in Massachusetts, Florida, Utah, Washington, California, Virginia and New York.

All of the cases "are within gay [and] bisexual men and other men who have sex with men," she said.

Walensky called for an approach "guided by science, not by stigma."

"This is a community that has the strength and has demonstrated the ability to address challenges to their health by focusing on compassion and science," she said in an apparent reference to the AIDS epidemic.

"While some groups may have a greater chance of exposure right now, infectious diseases do not care about state or international borders. They're not contained within social networks, and the risk of exposure is not limited to any one particular group," she warned.

Walensky implored Americans "to approach this outbreak without stigma and without discrimination."

'We shouldn't be surprised to see more cases'

The CDC is working to learn more about the outbreak: Samples from the nine identified cases were sent to the agency for additional confirmatory testing and genomic investigation, Walensky noted, and there are efforts to learn how each person contracted the virus.

Some of the nine cases have a recent history of international travel to areas with active monkeypox outbreaks, she said, but others do not.

Officials expect more cases to be diagnosed as the CDC has urged doctors and Americans to be on the lookout for symptoms.

"We shouldn't be surprised to see more cases reported in the US in the upcoming days. It's actually a sign that Americans are remaining vigilant, and health care providers and public health workers are doing their job," said Dr. Raj Panjabi, White House senior director for health security and biodefense.

As part of this outbreak, the CDC has been tracking multiple clusters of monkeypox that have been reported in early- to mid-May in several countries that don't normally report such infections, including regions in Europe and North America.

Monkeypox is rare in the United States, and the virus does not occur naturally in the country, according to the CDC. After the virus jumps from an animal to a human, human-to-human transmission can happen through close direct contact, such as via large respiratory droplets or lesions on the skin.

Monkeypox symptoms can include fever, headache, muscle aches and swollen lymph nodes. A characteristic of the disease is that it can cause lesions or pustules and a rash on the body, including the palms of the hands and the soles of the feet.

US plans to move vaccine to states that need it most

The US has mobilized vaccine for monkeypox to states that have reported cases and plans to move the vaccine where it may be needed, Walensky said Thursday.

"The US has the resources we need to help us respond to monkeypox in this country right now. We've been preparing for this type of outbreak for decades," she said.

The US has two preventive vaccines and two antiviral treatments that can be used for orthopox, the family of viruses that includes monkeypox.

"One of these vaccines, with the trade name of Jynneos, is approved for the prevention of monkeypox disease in adults 18 years of age and older," Walensky said. "CDC has mechanisms in place to move these products around the country so that they can be used for prevention or treatment for people who may benefit, wherever they may be."

Panjabi said that vaccination against monkeypox has been offered to health care workers in Massachusetts, where the first US case in this outbreak was identified last week.

"In Massachusetts, they got it as the Jynneos vaccine as of Sunday, and we're offering it to health care providers who've had high-risk exposure or are eligible according to the state and CDC guidance," Panjabi said.

CDC officials are recommending vaccination for people at highest risk of infection due to direct contact with someone who has monkeypox.

"Right now, while we are in the early phase of investigating this, we know that those at highest risk for infection are those who had contact with a known monkeypox patient, with the kind of contact that would facilitate spread. So those are the individuals we're really focusing on recommending vaccination for right now: post-exposure vaccination," said Dr. Jennifer McQuiston, deputy director of the CDC's Division of High Consequence Pathogens and Pathology.

"We continue to watch what is happening and think about whether wider vaccination recommendations would make sense, but at this time, we only have nine known cases, and we have contacts that we've identified associated with those cases that would likely most benefit from vaccines," McQuiston said. "And so that's where we're focusing our energies right now."