Suspected Monkeypox Cases Spread in U.S. as CDC Begins to Release Vaccine

The Centers for Disease Control and Prevention (CDC) has announced that it is beginning to release of a stockpile of monkeypox vaccine amid a rise in the small number of suspected U.S. cases.

The CDC said that one confirmed and four suspected cases of the viral disease, which is similar to smallpox but much less severe, had been detected in the U.S. as of Monday. Dr. Jennifer McQuiston, deputy director of the CDC's Division of High Consequence Pathogens and Pathology, said during a press call that the country's supplies of the two-dose Jynneos vaccine—which is licensed to prevent both monkeypox and smallpox—was being released to high-risk groups.

"It's likely that there are going to be additional cases reported in the United States," McQuiston said. "We're working now to develop recommendations to ensure that the vaccine supplies that we have are available to those who need it and that doctors can use it to decide what's right for their patients."

"We have a good stock of vaccine," she added later. "Right now we have over 1,000 doses of [the Jynneos vaccine] available and we expect that level to ramp up very quickly in the coming weeks as the company provides more doses to us."

Monkeypox Cases Spread Vaccine Release CDC
The CDC said that it was releasing stockpiles of monkeypox vaccine as a small number of suspected U.S. cases grew on Monday. Monkeypox lesions are pictured on a person's hand in this CDC-supplied photo from May 27, 2003. CDC/Getty

The Jynneos vaccine is one of two available vaccines that could be used to prevent monkeypox. The U.S. has a stockpile of more than 100 million doses of the other older-generation vaccine, known as ACAM2000, which McQuiston said would require "serious discussion" before being used, due to "potential significant side effects."

When asked whether any of those in contact with the confirmed or suspected monkeypox patients had been given the Jynneos vaccine, which the U.S. ordered millions of additional doses of last week, McQuiston said that there had 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."

Despite not being officially confirmed, the four suspected U.S. cases are highly likely to be monkeypox since testing has confirmed that the pathogen involved belongs to the orthopoxvirus family—which contains both monkeypox and smallpox. The CDC expects to analyze samples from the cases for final confirmation this week. A small outbreak of monkeypox, which is typically found only in Africa, first occurred in the U.S. in 2003.

Smallpox was declared globally eradicated in 1980, with no naturally occurring cases being detected since then. The Jynneos vaccine was developed partly due to ongoing concerns that the virus—which had a fatality rate of around 30 percent—could make a return as a bioterrorism agent. Monkeypox remains rare and is believed to have a fatality rate of between 1 and 10 percent.

There are currently at least 92 cases of monkeypox in 12 countries, with many more potential cases under investigation, according to the World Health Organization. On Sunday, President Joe Biden said that the world "should be concerned" about the virus spreading further.

Newsweek reached out to the CDC for comment.