More Severe Mpox Strain Detected in NYC

Health officials warn of clade I mpox case, which causes more serious illness.

Mar. 14, 2026 at 4:36pm

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New York City health officials have reported the first case of the more severe clade I strain of mpox in the city. Clade I mpox is known to cause more serious disease and higher rates of death compared to the more common clade II strain. The infected individual recently traveled to Europe and is now isolating.

Why it matters

The detection of the more dangerous clade I strain raises concerns about the potential for a more serious mpox outbreak in New York City. While the overall risk remains low, health officials are urging at-risk residents to get vaccinated to prevent the spread of this more virulent form of the virus.

The details

The NYC Health Department confirmed the first case of clade I mpox in the city on Friday. Clade I is one of two known types of mpox virus, and it is associated with more severe illness and higher mortality rates compared to the more common clade II strain. This is the 12th reported case of clade I mpox in the United States. The infected individual recently traveled to Europe and is now isolating until their symptoms subside.

  • The first case of clade I mpox was detected in New York City on March 14, 2026.

The players

NYC Health Department

The public health agency responsible for monitoring and responding to infectious disease outbreaks in New York City.

Dr. Alister Martin

The Health Commissioner of New York City, who issued a statement about the clade I mpox case.

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What they’re saying

“There is no known local transmission of mpox clade I in New York City and the risk remains low for New Yorkers. The NYC Health Department recommends that New Yorkers who are at risk for mpox receive and complete the two-dose vaccine series that works to prevent mpox.”

— Dr. Alister Martin, Health Commissioner, New York City (cbsnews.com)

What’s next

Health officials will continue to monitor the situation and provide updates on the spread of the clade I mpox strain in New York City.

The takeaway

The detection of the more severe clade I mpox strain in New York City underscores the importance of vaccination and vigilance, especially for high-risk populations. While the overall risk remains low, this development serves as a reminder that public health officials must remain proactive in addressing emerging infectious disease threats.