NIH Study Finds Mpox Can Infect and Replicate in the Brain

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Researchers at the U.S. National Institutes of Health (NIH) have discovered that the mpox virus can persist and replicate within the human brain. The finding comes from a detailed autopsy of a 38-year-old man with advanced HIV who was infected with the clade IIb strain of mpox and died after more than seven months of antiviral therapy.

Why it matters

The NIH findings suggest that mpox is capable of spreading significantly further than the skin lesions that typically characterize the disease, and that the virus can develop resistance to antiviral drugs like tecovirimat, particularly in immunocompromised individuals. This discovery highlights the risks in regions where mpox is spreading among populations with high rates of untreated HIV, especially in parts of Africa.

The details

During the autopsy, scientists found the virus infecting the brain and continuing to multiply there, although viral levels in the brain were lower than those found in other tissues. The case also revealed that the virus had developed resistance-associated mutations, including those linked to resistance to tecovirimat, an antiviral drug used to treat mpox.

• The NIH findings were released as a preprint on April 9, 2026.
• The case involved a 38-year-old man who was infected with the mpox clade IIb strain and died after more than seven months of antiviral therapy.

What’s next

Researchers warned in September 2025 that cuts to global health funding are undermining HIV care and the response to outbreaks, which may create an environment where infections last longer and lead to more severe disease manifestations.