Health Experts Raise Alarm Over Emergence of Deadlier Mpox Strain With Evidence of Local Transmission

Health officials in California have confirmed three cases of a newly detected, potentially more severe strain of mpox, known as Clade I, in patients with no recent history of international travel—a first for the United States. The cases, identified in Long Beach and Los Angeles County, required hospitalization for all patients involved, though all are reportedly recovering at home .

Public health leaders warn that this development indicates potential community spread, as none of the affected individuals had traveled overseas to high-risk regions or had known exposure to imported cases. This suggests that the virus is now transmitting locally, raising the stakes for surveillance and prevention measures .

Dr. Muntu Davis, Los Angeles County health officer, described the emergence as"concerning," emphasizing the need for"continued surveillance, early response and vaccination" to prevent wider outbreaks .

Mpox, caused by the monkeypox virus, is a zoonotic orthopoxvirus that has gained global attention since the 2022 outbreak, which saw more than 97,000 confirmed cases across 118 countries . The World Health Organization declared mpox a public health emergency of international concern in August 2024 .

Traditionally, mpox cases outside Africa were linked to travel from endemic regions. However, recent genetic investigations have identified new variants such as Clade Ib and Clade I, which carry mutations associated with increased transmissibility and potential for more severe illness .

These new variants have fueled large outbreaks in Central and East Africa, with the Democratic Republic of Congo, Sierra Leone, and Malawi reporting over 139,000 suspected cases and nearly 1,800 deaths in 2024-2025 . The Clade I and Clade Ib strains are characterized by mutations in the APOBEC3 gene, which are believed to enhance human-to-human transmission, including through close and intimate physical contact .

Countries such as Rwanda, Uganda, Kenya, and Burundi have reported confirmed cases of the Clade Ib variant, underscoring the risk of further regional—and now international—spread

Mpox is primarily spread through direct skin-to-skin contact with infectious lesions, scabs, or body fluids, as well as through sharing living spaces or personal items with an infected person . Intimate contact, including sexual activity, massage, or cuddling, has been highlighted as a significant mode of transmission for the current outbreak .

Although anyone can contract mpox, recent outbreaks—especially those outside Africa—have disproportionately impacted communities of gay, bisexual, and other men who have sex with men. Health agencies stress that while the disease is not confined to any one group, tailored public health messaging and stigma-free education are critical to ensuring early diagnosis and care .

Symptoms of mpox include fever, headache, muscle aches, and a characteristic rash that often spreads from the face to other parts of the body. Complications can be severe, especially for immunocompromised individuals, and there have been reports of coinfection with HIV in some cases .

In light of the new Clade I strain's detection, health officials are urging at-risk residents—particularly those with multiple or anonymous sexual partners—to receive both doses of the mpox vaccine . While the overall risk to the public remains low, authorities are prioritizing vaccination campaigns, early case identification, and robust genomic surveillance to prevent further spread .

There are currently no mpox-specific antiviral drugs widely approved, though treatments such as tecovirimat, cidofovir, and ribavirin are being considered in clinical settings . Research into mRNA-based vaccines and new antiviral regimens is ongoing, with early results from preclinical studies showing promise .

Experts emphasize that effective response requires both scientific innovation and community engagement. Stigma-free and inclusive health communication is highlighted as essential, especially in LGBTQ+ communities that may already experience barriers to care due to discrimination or lack of culturally competent health services .

The detection of the Clade I variant in the United States, with no apparent links to international travel, is a stark reminder of the interconnectedness of global health threats. The trajectory of the outbreak in Africa—where the virus has begun to affect broader demographics, including children and healthcare workers—signals the need for ongoing vigilance, investment in surveillance infrastructure, and rapid public health response .

The World Health Organization and Centers for Disease Control and Prevention continue to urge countries to strengthen early warning systems, enhance laboratory capacity, and ensure equitable access to vaccines and treatments .

LGBTQ+ advocacy organizations have underscored the importance of culturally competent outreach in response efforts, warning against the stigmatization of communities that may be disproportionately affected by the outbreak . Many are calling for targeted vaccination drives, accessible testing, and mental health support, as well as collaboration with trusted community leaders to ensure information reaches those most at risk.

As the situation evolves, LGBTQ+ leaders and public health experts alike stress the need to balance urgent action with respect for the dignity and rights of all individuals, reaffirming that viruses do not discriminate and that effective response depends on solidarity, scientific rigor, and inclusion .