Originally Published: 23 MAY 22 15:44 ET

By Jacqueline Howard and Virginia Langmaid, CNN

(CNN) -- The United States is responding to a request for the release of monkeypox vaccine from the nation's Strategic National Stockpile as a global outbreak of cases is under investigation.

There is one confirmed case of monkeypox and four suspected cases in the United States, the US Centers for Disease Control and Prevention said Monday.

"I can report that there has been a request for release of the Jynneos vaccine from the National Stockpile for some of the high-risk contacts of some of the early patients, so that is actively happening right now," Dr. Jennifer McQuiston, deputy director of the Division of High Consequence Pathogens and Pathology within the CDC's National Center for Emerging and Zoonotic Infectious Diseases, said Monday.

McQuiston said the United States has a "good stock" of vaccine because it has been preparing for the possibility of needing to use doses for smallpox.

In the United States, the two-dose Jynneos vaccine is licensed to prevent smallpox and specifically to prevent monkeypox.

"Right now, we have over 1,000 doses of that available, and we expect that level to ramp up very quickly in the coming weeks as the company provides more doses to us," McQuiston said.

There is another smallpox vaccine licensed in the United States, ACAM2000, that could be used to prevent monkeypox, she said, and the country has more than 100 million doses.

"ACAM2000 is an older-generation smallpox vaccine that has some potential significant side effects with it. So a decision to use that widely would have to have some serious discussion behind it," McQuiston said.

Overall, "we are hoping to maximize vaccine distribution to those that we know would benefit from it," she said. "Those are people who've had contact with a known monkeypox patients, health care workers, very close personal contact, and those in particular who might be at high risk for severe disease."

The confirmed US monkeypox case is in a man in Massachusetts, and the four cases of orthopox are in men in New York, Florida and Utah, the CDC says. Orthopox refers to pox viruses in general.

McQuiston said health care providers should assume that these orthopox cases are monkeypox.

"It is likely that there are going to be additional cases reported in the United States," she said.

McQuiston said the CDC expects to receive samples from the four suspected cases "today or tomorrow" for further analysis. Labs within the CDC's Laboratory Response Network can test for an orthopox virus, and then confirmation of monkeypox specifically is done at the agency through PCR tests, which take "a couple of hours" to run, she said.

"From the time that CDC gets a specimen, we could do our monkeypox confirmatory PCR tests likely the same day. We've been seeing turnaround of a couple of days really, from the time a suspect patient might come to a doctor's attention to they can get that initial state LRN laboratory results," McQuiston said.

CDC sequencing of the sample from the confirmed case in Massachusetts went "really quickly," and within 48 hours, researchers were able to see that it closely matched that of a case in Portugal.

"This process previously took up to two weeks, but we were able to get it posted within two days because we feel like this kind of public sharing of early sequence data is going to be important for all countries to do so that we can all better understand how the virus is spreading across the globe," McQuiston said.

Monkeypox is not spread through sex itself but can be spread through contact during sex, said Dr. John Brooks, the CDC's chief medical officer of HIV prevention.

"Monkeypox is not a sexually transmitted infection in the typical sense, but it can be transmitted during sexual and intimate content, as well as with personal contact and shared bedding and clothing," Brooks said Monday. Many of those affected in the latest outbreak of the virus are gay and bisexual men, he said.

Brooks said the rash is "showing up in different parts of the body than we typically expect to see it," including the genital and perianal area.

"In some cases, it has produced anal or genital lesions that look like other diseases like herpes, chickenpox or syphilis. So anyone with a rash or lesion around or involving their genitals, their anus or any other place that they have not seen it before, get fully evaluated, both for that rash but particularly for sexually transmitted infection and other illnesses that can cause rash," he said.

"What we're trying to do by bringing attention to the fact that some of these cases have had a genital and perianal presentation is just to remind people that people may come in for an evaluation of what they think is an STD, but we'd like the provider to think 'could it be monkeypox as well?' if the circumstances fit the story."