Los Angeles county health officials have confirmed three cases of a rare and potentially severe strain of mpox virus, known as Clade I mpox. These cases mark the first known local transmission of this strain in the United States, raising public health concerns about a possible spread within the community.
According to the Los Angeles County Department of Public Health (LACDPH), all three infected individuals were hospitalized but later discharged for home recovery. What’s particularly alarming is that none of them had recently traveled to Africa, where this strain has historically circulated.
“The confirmation of a third case with no travel history raises concerns about possible local spread in Los Angeles County,”
said Dr. Muntu Davis, Los Angeles County Health Officer.
The California Department of Public Health (CDPH) also issued an alert, warning that the virus could be spreading among certain populations, including gay and bisexual men. Health officials, however, emphasized that the risk to the general public remains low, though vaccination is strongly encouraged for high-risk groups.
What Is Mpox?
Mpox (formerly known as monkeypox) is a viral zoonotic disease — a disease transmitted from animals to humans — caused by the mpox virus, a member of the Orthopoxvirus family, which also includes smallpox.
According to the World Health Organization (WHO), mpox commonly causes fever, painful rash, swollen lymph nodes, and fatigue. Severe cases may lead to complications like sepsis, encephalitis (brain inflammation), and bacterial skin infections.
The Two Major Clades of Mpox
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Clade I (Central African strain): Causes more severe disease and higher hospitalization rates. Historically found in the Congo Basin.
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Clade II (West African strain): Generally milder and was responsible for the global mpox outbreak in 2022.
The 2025 Los Angeles cases involve Clade I mpox, which is considered more dangerous than Clade II.
First Local Spread of Clade I Mpox in the U.S.
The first case of Clade I mpox in this cluster was reported in Long Beach on October 14, 2025, followed by two more cases in other parts of Los Angeles County on October 16 and 17. These cases are the first confirmed instances of local transmission of this strain in the United States.
So far, there have been nine cases of Clade I mpox nationwide in 2025, most linked to international travel. The three Los Angeles cases are different because they show no travel history or clear connection, suggesting community transmission.
Public health experts are now conducting contact tracing and genetic testing to understand how this strain entered and spread locally. Although all three patients were hospitalized, no deaths have been reported.
How Does Mpox Spread?
The Centers for Disease Control and Prevention (CDC) states that mpox spreads through direct contact with the rash, scabs, or bodily fluids of an infected person. Transmission may occur through:
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Intimate or sexual contact (skin-to-skin, kissing, or intercourse)
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Contact with contaminated materials, such as bedding or clothing
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Prolonged face-to-face contact with respiratory secretions
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Animal bites, scratches, or handling infected wild animals
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Mother-to-child transmission during pregnancy or childbirth
Mpox is not airborne like COVID-19, meaning you cannot get it from casual contact or being in public spaces.
“You don’t get it from going to yoga, public transport, or grocery stores. It’s something that’s really intimate,”
said Dr. Peter Chin-Hong, infectious disease expert at UC San Francisco.
Symptoms of Mpox Infection
Mpox symptoms typically appear 3 to 17 days after exposure, with illness lasting about 2 to 4 weeks.
Common Symptoms:
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Fever and chills
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Swollen lymph nodes
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Muscle and back pain
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Headache
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Exhaustion
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Sore throat, nasal congestion, or cough
The Rash:
The rash evolves in stages — flat spots, raised bumps, then pus-filled blisters — and eventually scabs over. It can appear on the face, hands, feet, or genitals. In Clade I cases, the lesions are often more painful and widespread, with a higher risk of secondary infections or scarring.
Prevention and Vaccination
The most effective preventive measure is the Jynneos vaccine, given in two doses. Studies show it provides 86–89% protection against mpox infection and helps reduce symptom severity even if infection occurs.
Who Should Get Vaccinated?
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People exposed to mpox or in close contact with confirmed cases
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Individuals with multiple sexual partners in affected areas
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Healthcare and laboratory workers handling Orthopoxviruses
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Gay, bisexual, and transgender individuals at higher risk
“The risk of severe disease is highest for people with weakened immune systems. It’s critical to protect yourself by getting both doses of the vaccine,”
said Dr. Rita Nguyen, Assistant State Public Health Officer.
What To Do If You Suspect Mpox
If you develop an unexplained rash or suspect exposure, you should:
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Seek medical attention immediately. Testing and early care help prevent complications.
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Isolate at home until all lesions have healed.
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Inform close or sexual contacts so they can monitor for symptoms.
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Wear a mask in public to minimize potential spread.
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Clean and disinfect surfaces and personal items regularly.
“Anyone with an unexplained rash or lesions should seek care promptly. Speak openly with intimate partners and your healthcare provider,”
said Dr. Cliff Okada, Public Health Physician in Long Beach.
How Serious Is This Outbreak?
The confirmation of local Clade I mpox transmission is significant but not yet a cause for public panic. Current data show only three cases, all under medical management and recovery.
Officials emphasize that the general public’s risk remains low, but vigilance and vaccination are essential to prevent further spread.
The CDC and WHO are collaborating with California health authorities to conduct genetic sequencing and epidemiological surveillance to track the virus’s behavior in U.S. populations.
Global Perspective
Mpox remains endemic in Central and West Africa, where both Clade I and Clade II circulate. Transmission often occurs through contact with wild animals like rodents or primates.
Since the 2022 global outbreak, over 87,000 cases have been reported in 110 countries. The majority involved the milder Clade II strain. However, the emergence of Clade I in Los Angeles suggests the virus may be adapting to local human networks — a development requiring ongoing monitoring.
Key Takeaways
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Three Clade I mpox cases confirmed in Los Angeles County in October 2025.
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None of the patients had travel history, suggesting local spread.
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All three were hospitalized but are recovering.
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Public risk remains low, but vaccination and awareness are critical.
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The Jynneos vaccine provides strong protection (≈86–89%).
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High-risk populations — especially men who have sex with men — are urged to get vaccinated.
References
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Los Angeles County Department of Public Health (LACDPH) – Press Release, Oct 17, 2025
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California Department of Public Health (CDPH) – Mpox Advisory
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Centers for Disease Control and Prevention (CDC) – Mpox Guidelines
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World Health Organization (WHO) – Mpox Fact Sheet
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UC San Francisco Health – Expert Commentary by Dr. Peter Chin-Hong
Frequently Asked Questions About Clade I Mpox
1. What is Clade I mpox?
Clade I mpox is a more severe strain of the mpox virus, historically found in Central Africa. It’s associated with higher hospitalization rates and, in rare cases, severe illness.
2. Is Clade I mpox spreading in the United States?
Yes. As of October 2025, Los Angeles County has confirmed three locally transmitted cases of Clade I mpox — the first of their kind in the U.S.
3. How can I protect myself from mpox?
Avoid close or sexual contact with anyone showing rash or lesions, disinfect personal items, practice safe sex, and get the two-dose Jynneos vaccine if you’re at risk.
4. Is the mpox vaccine effective?
Yes. The Jynneos vaccine provides about 86–89% protection against infection and helps reduce severity if infection occurs.
5. Should the public be worried?
No, the risk remains low for the general public. Most infections require intimate contact for transmission, and vaccination remains the best preventive tool.
Medically reviewed by Dr. Subarna Debbarma, Physiotherapist & Health Science Writer
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