CDC Warns About Worrisome New Mpox Outbreak


An outbreak of mpox (formerly called monkeypox) in the Democratic Republic of Congo (DRC) is worrying public health officials. This is the largest outbreak in the country’s history and is caused by a deadlier type of the virus than the one that spread across the globe in 2022-2023. Unlike other outbreaks in the DRC, this one appears to be spreading through sexual contact.

The World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) are urging caution for travelers and asking clinicians to be on the lookout for people with symptoms.

Mpox Viruses

There are two types of virus that cause mpox infections usually referred to as clade I and clade II. The worldwide outbreak last year was caused by the clade II type which causes more mild infections and has a fatality rate less than 1%.

Clade I is more infectious, causes more serious illness, and has a much higher fatality rate (around 10%). In the past, clade I outbreaks have been localized and linked primarily to contact with infected animals. In this outbreak, though, the infection has been passed on through sexual contact, household contact, and in healthcare settings.

There have been over 12,500 suspected cases of mpox (clade I) in the DCR with 581 deaths since January 2023. In contrast, there were over 91,700 cases of mpox (clade II) in 116 countries between January 2022 and October 2023 and 167 deaths.

Mpox and Sexual Contact

Mpox is spread by close, personal contact. It causes a rash of pus-filled blisters that start on the face and spread over the body, including the palms of the hands and the soles of the feet. Blisters can also appear on the genitals. Direct contact with this rash can spread the virus even if the blisters have scabbed over. The virus can also be spread through saliva, respiratory secretions, and the skin around the anus, rectum, or vagina.

The kind of direct, personal contact that can spread mpox often occurs during sex. So mpox can be passed on during oral, anal, or vaginal sex. It can also be passed on during hugging, kissing, or massage.

It’s possible for mpox can be spread through fabric (like clothes or sheets) and objects (like fetish gear and sex toys) that haven’t been properly cleaned, but that is less likely.

Sexual transmission—primarily between men who have sex with men—was the major driver of the global outbreak. Sexual transmission has not been a driver in a clade I outbreak up until now, but experts worry that this may be happening in DRC and that the outbreak could spread beyond the country.

Vaccines and treatments

There is a vaccine that protects against mpox. The CDC suggests the vaccine for men who have sex with men who:

  • have more than one sexual partner
  • engage in anonymous sex
  • have HIV or an otherwise weakened immune system
  • have had one or more STIs in the last 6 months

Unfortunately, the vaccine is not currently available in DRC in part because the government has not cleared it for use. Some experts fear that even if the DRC authorized distribution of the vaccine, men who have sex with men would not get it. Same-sex relationships are taboo in the country, and men might not want to admit they needed the vaccine.

There is also a medication, called TPOXX or tecovirimat, that has shown some success in treating mpox. Large-scale studies have not been completed, and it’s not yet approved by the FDA. It has been used in some places around the world (including in the U.S.) under emergency use protocols, but the Congolese government has not moved to make this available either.

In the United States

The CDC has told clinicians to be on the lookout for symptoms of mpox, including the telltale blisters. In the last outbreak, mpox blisters appeared on the genitals and were often misdiagnosed as herpes or syphilis. Clinicians should ask patients presenting with possible mpox symptoms whether they or any of their partners have traveled to DRC.

The agency has also suggested that people traveling to DRC practice enhanced precautions to avoid mpox. Travelers should avoid contact with sick people and any live or dead wild animals.