NYC Confirms First Case of More Severe Mpox Strain

New York City health officials have confirmed the city’s first case of a more severe strain of mpox, known as clade I, than the one that caused a global outbreak in 2022. The case is travel-related and there is currently no evidence of local transmission. This development prompts renewed attention to mpox prevention and vaccination efforts.

Understanding the Two Mpox Clades

Mpox, formerly known as monkeypox, is a contagious disease caused by the mpox virus. There are two main clades, or variants, of the virus: clade I and clade II. The 2022 outbreak in New York City and the U.S. Was driven by clade II. The current case involves clade I, which has been associated with more serious illness and a higher fatality rate than clade II [1].

Recent Mpox Cases in NYC and Globally

As of March 12, 2026, 45 people in New York City have tested positive for mpox since January 1, 2026. There have been 16 cases reported in the last month (February 8, 2026 to March 7, 2026) [1]. Since January 1, 2024, an outbreak of clade I mpox has been ongoing in the Democratic Republic of the Congo and other countries in Central and Eastern Africa [1]. As of March 14, 2026, eleven cases of clade I have been identified across the United States, all linked to recent travel to affected areas in Africa or contact with travelers [3].

How Mpox Spreads

In the U.S., mpox is primarily spreading through close or intimate contact, including oral, anal, and vaginal sex, hugging, kissing, biting, cuddling, and massaging [1]. While not classified as a sexually transmitted infection, cases have predominantly been observed among men who have sex with men, transgender people, and their social networks [1] [2]. Anyone who has been in close contact with someone who has mpox is at risk of infection.

Symptoms of Mpox

The most common symptom of mpox is a painful rash, which can appear on the hands, feet, chest, face, or near the genitals [2]. Other symptoms may include fever, chills, and flu-like symptoms.

Prevention and Vaccination

Health officials are urging individuals at risk to receive the two-dose JYNNEOS vaccine, which can reduce the risk of infection and lessen symptom severity [2]. Those who may benefit from vaccination include men who have sex with men, transgender and nonbinary individuals, and anyone planning to travel to countries where the virus is spreading. Vaccination sites are available throughout New York City; information can be found at nyc.gov/mpox or by calling 311.

Key Takeaways

• New York City has confirmed its first case of clade I mpox, a more severe strain than the one responsible for the 2022 outbreak.
• The case is travel-related, with no known local transmission at this time.
• Mpox spreads through close or intimate contact.
• The JYNNEOS vaccine is available and recommended for those at risk.