Formerly known as monkeypox, the virus has dwindled in the US and is no longer considered a public emergency. Here's what to know about it.
Mpox, formally known as monkeypox, has faded to the point that US health officials no longer consider it a public health emergency. Cases have dwindled significantly since the peak of the outbreak last summer, with only a handful being reported daily in January and February, according to data from the US Centers for Disease Control and Prevention.
Health experts have credited the uptake of Jynneos, the mpox vaccine, as well as a shift in sexual health behavior among people most affected by mpox -- gay men and others in the men who have sex with men, or MSM, community -- for keeping the global outbreak from spreading more widely in the US. Another element is the fact that mpox is more difficult to spread, compared with respiratory illnesses for example, because it requires close contact with someone with mpox.
Still, even as cases of mpox remain controlled in wealthier countries like the US and the UK, the virus is still spreading in African countries, which have less access to treatments and vaccines. Prior to the global outbreak of 2022, mpox was primarily concentrated in African countries. And as the science journal Nature reports, global complacency in regard to areas of the world still experiencing the brunt of the virus could allow mpox to spread widely again -- perhaps in the form of a more deadly subvariant.
Major cities in the US that were hit harder by the outbreak last summer, including San Francisco and New York, still offer vaccinations for people who want one and are at higher risk of getting the disease. And other therapeutics, as well as best practices for avoiding transmitting mpox to your close contacts, remain the same this year.
Here's what to know.
Mpox, which is now formally referred to as mpox after the World Health Organization renamed the virus in November, is a disease caused by an orthopoxvirus that belongs to the same family as the viruses that cause smallpox and cowpox. It's endemic in West and Central Africa, and reports of it in the US prior to 2022 have been rare but not unheard of. (There were two reported cases in 2021 and 47 cases in 2003 during an outbreak linked to pet prairie dogs.) Mpox is a zoonotic disease, which means it's transmitted from animals to humans.
Of the two types of the virus -- Clade I and Clade II -- Clade II is the outbreak strain in the US, according to the CDC, and it's typically less severe than Clade I. Of more than 30,000 cases of mpox, CDC data shows, 28 deaths occurred in the US during the outbreak.
The 2022 pox outbreak was thought to be linked to a case detected by a Nigerian infectious disease doctor in 2017, according to an NPR report. Dr. Dimie Ogoina identified a case with characteristics that more closely resemble mpox now, with cases spreading between men with a link to sexual contact. His and his teammates' warnings to the broader medical community may have fallen on deaf ears as the outbreak spread beyond Nigeria, according to the report.
In August, mpox was declared a public health emergency in the US, with the declaration meant to open up more funding and resources needed to respond to the outbreak, including vaccines, testing and treatments. The government's response to the crisis was criticized earlier in the outbreak, in part over inadequate vaccine access and testing resources. However, citing very low case numbers and a promise to not "take our foot off the gas," Department of Health and Human Services Secretary Xavier Becerra announced in December that health officials weren't planning on renewing the emergency past January.
Mpox mostly spreads between people through very close contact, according to the CDC, which includes skin-to-skin contact through sex or prolonged kissing. You usually need direct contact with an mpox rash or scabs, or contact with someone's saliva or mucus that has the virus in order for it to spread. The risk of getting it from a contaminated surface or object is currently "considered low," the CDC says.
However, as of February 2023, the CDC says new data shows some people are able to spread the virus between one and four days before symptoms appear, so you should take precautions if you were a close contact of someone with mpox.
Cases in the US and other countries that don't normally experience the virus have primarily been linked to sexual contact among gay men and other MSM, but anyone with close contact with someone with the virus can get it. Gay and bisexual communities tend to have particularly "high awareness and rapid health-seeking behavior when it comes to their and their communities' sexual health," Dr. Hans Henri P. Kluge, the WHO's regional director for Europe, said in a statement at the end of May, noting that people who sought health care early in the outbreak should be applauded.
The "close" in "close contact" is a key element in the transmission of mpox. That, along with the fact that the virus that causes mpox appears to have a slower reproduction rate than the COVID-19 virus, sets it apart from the ongoing COVID-19 pandemic, Dr. Tom Inglesby, director of the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health, said in June at a media briefing.
The test involves taking a swab from a lesion or sore to test for the virus that causes mpox. For people who first develop flulike symptoms before lesions or sores appear, that may mean waiting for lesions or "pox" to appear. If you have symptoms, get tested and isolate at home.
Antiviral medication like tecovirimat, or TPOXX, can be used in people who are at risk of getting severely sick from mpox, according to the CDC, including some people with HIV or eczema. While it's originally meant for treating smallpox, it's been used in mpox cases because the viruses are similar. If you have a health condition that makes you immunocompromised, you should reach out to your health care provider for therapeutic options and more guidance, especially if you haven't had an mpox vaccine (which can also be given post-exposure).
Symptoms of mpox in humans are similar to (but usually significantly milder than) those of smallpox, which the WHO declared eliminated in 1980.
An mpox infection can begin with flu-like symptoms -- including exhaustion, headache, fever, muscle aches, chills, respiratory symptoms and swollen lymph nodes -- followed by a rash, but some people will only develop the rash, according to the CDC. The mpox rash or individual sores can look like pimples or blisters and can be found pretty much anywhere on the body, including the hands, genitals, face, chest and inside the mouth or anus. Lesions can be flat or raised, full of clear or yellowish fluid and will eventually dry up and fall off. For some people, they can be very painful.
You can spread mpox until the sores heal and a new layer of skin forms, according to the CDC. People will most likely develop symptoms within three weeks of being exposed, per the CDC.
Read more: Mpox Symptoms to Look Out For
Yes. The US Food and Drug Administration has approved Jynneos to prevent smallpox and mpox. Because mpox is so closely related to smallpox, vaccines for smallpox are also effective against mpox. In addition to Jynneos, the US has another smallpox vaccine in its stockpile, called ACAM2000. Because ACAM2000 is an older generation of vaccine with a different side effect profile, it isn't recommended for everyone, including people who are pregnant.
Jynneos is the vaccine currently available to people who are at higher risk of getting mpox, or may have already been exposed to it. During the outbreak, the FDA authorized a new way of giving people Jynneos meant to stretch out the limited supply through intradermal vaccination, which requires a lower dose of vaccine compared with subcutaneous injection.
People at higher risk of being exposed to mpox can get the vaccine, though eligibility and availability ultimately depends on where you live and your local health department. Gay men and other MSM who've had more than one sexual partner in the past six months or a newly diagnosed sexually transmitted infection; people who've had sex at a public sex venue or public event in the past six months; those who anticipate participating in the above scenarios and the sexual partners of those folks should all be eligible for an mpox vaccine, per the CDC. People with a weakened immune system, including an HIV infection, should also get the vaccine if they could have a future exposure. Certain health care workers may also be recommended one.
Vaccinating people who've been exposed to mpox is what Dr. Amesh Adalja, an infectious-disease expert and senior scholar at the Johns Hopkins Center for Health Security, calls "ring vaccination," where health officials isolate the infected person and vaccinate their close contacts to stop the spread.
Dr. Daniel Pastula, chief of neuroinfectious diseases and associate professor of neurology, medicine and epidemiology at the University of Colorado Anschutz Medical Campus, said the vaccine is used in people who've been exposed but aren't yet showing symptoms of mpox, because the incubation period for the disease is so long.
"Basically what you're doing is stimulating the immune system with the vaccine, and getting the immune system to recognize the virus before the virus has a chance to ramp up," Pastula said.
Though health care and lab professionals who work directly with mpox are recommended to receive smallpox vaccines (and even boosters), the original smallpox vaccines aren't available to the general public and haven't been widely administered in the US since the early 1970s. Because of this, any spillover or "cross-protective" immunity from smallpox vaccines would be limited to older people, the WHO said.