The Centers for Disease Control and Prevention will release some Jynneos smallpox vaccines from the nation’s Strategic National Stockpile to help prevent the spread of confirmed cases of monkeypox. The vaccine will be available to close contacts and certain health care workers who might have been exposed to monkeypox.

Providing vaccinations to a small circle of people who come in direct contact with someone who has a viral infection like monkeypox is called “ring” vaccination and it’s a method that has been used successfully to prevent larger outbreaks or control certain diseases.

The CDC said Monday that there is one confirmed case and four suspected cases in the United States. A case in Massachusetts has been confirmed and public health officials are investigating four cases: one each in New York and Florida and two in Utah.

But those numbers could soon grow. Right now, at least a dozen countries have seen small outbreaks of the virus and the World Health Organization reports that 131 have been confirmed, with another 106 suspected.

Health officials worldwide are looking at their smallpox vaccines and considering how they will treat monkeypox if cases continue to spread. The World Health Organization reportedly stockpiles more than 30 million smallpox vaccine doses, but there are some questions about their potency after being stored for years, The New York Times reported.

The CDC said the U.S. emergency drug stockpile includes two vaccines the U.S. Food and Drug Administration says can be used against monkeypox. Both target its cousin, smallpox.

The older of the two vaccines, ACAM2000, can have some serious side effects. The New York Times reported that this vaccine cannot be used for those with compromised immune systems, such as people who received solid organ transplants or who have certain health conditions.

The newer, two-dose Jynneos vaccine was approved by the FDA in 2019 for both smallpox and monkeypox and is believed to have fewer side issues. CDC Deputy Director Dr. Jennifer McQuiston said the stockpile contains more than 1,000 doses — with more expected from the manufacturer. It can be given to high-risk adults 18 and older, according to Reuters.

McQuiston said the United States has more than 100 million doses of ACAM2000 on hand.

The U.S. also has more than 2 million doses of an antiviral called tecovirimat, approved to treat smallpox in those who become infected, the CDC said. The manufacturer is working on creating an intravenous form.

About monkeypox

According to the CDC, monkeypox is most common in parts of Africa, including Congo and Nigeria. In 2021, two travel-related cases were confirmed in the United States. Prior to that, the largest outbreak was in 2003, when 47 confirmed and probable cases were linked to prairie dogs imported from Ghana. The CDC said that was the first time human monkeypox was reported outside of Africa.

The virus causes a rash and pus-filled blisters. Monkeypox spreads easily through close contact including via bodily fluids and respiratory droplets or even contaminated cloth. In most cases, the infection takes care of itself within about three weeks. But it can also create deadly complications.

Monkeypox feels like the flu at first, and leads to symptoms like chills, exhaustion and weakness. Symptoms also include fever, headache, muscle or back pain and swollen glands.

Then it turns into a rash that can start on the face and in the mouth, and spread to the body, including the palms of the hands and soles of the feet. Next, lesions begin to fill with pus, then eventually scab over and fall off.

Testing and tracking outbreaks

As CNN reported, “McQuiston said the CDC expects to receive samples from the four suspected cases (Tuesday or Wednesday) for further analysis. Labs within the CDC’s Laboratory Response Network can test for an orthopoxvirus, and then confirmation of monkeypox specifically is done at the agency through PCR tests, which takes a couple of hours to run.”

Monday, the European version of the CDC cautioned that those who are infected should avoid close contact with pets because it’s possible if the infection spreads among the animal population, it could become endemic in Europe. It, however, deemed the risk to be somewhat low.

Sexual activity is a suspected link in some of the cases globally, but the tie is believed to be from the close contact involved, Dr. John Brooks, the CDC’s chief medical officer of HIV prevention, told CNN.

“Monkeypox is not a sexually transmitted infection in the typical sense,” he said, “but it can be transmitted during sexual and intimate contact, as well as with personal contact and shared bedding and clothing.”

He added that a “notable faction of cases” in the global outbreak — but not all, by any means — have been among gay and bisexual men.

“Some groups may have a greater chance of exposure right now, but by no means is the current risk of exposure to monkeypox exclusively to the gay and bisexual community in the U.S.,” Brooks said. “Anyone, anyone, can develop (and) spread monkeypox infection, but ... many of those affected in the current global outbreak identified as gay and bisexual men.”

President Joe Biden expressed concern about monkeypox over the weekend, but assured reporters during a joint press conference with Japan’s Prime Minister Fumio Kishida that the United States has enough vaccine stockpiled to meet the needs.