New Virus Threats Looming in 2026

Infectious disease experts are closely watching several viruses that could cause significant outbreaks in 2026. Influenza A remains a constant threat due to its rapid mutation rate. A particular focus is on highly pathogenic avian influenza H5N1, which recently spread to U.S. dairy cattle, creating concern for adaptation to humans and potential human-to-human transmission. Scientists are actively working on vaccines against H5N1, as current ones likely offer no protection.

Mpox virus, formerly known as monkeypox, has also become an established global threat. Following a major 2022 outbreak of the milder clade II, several African countries are reporting increased clade I cases, and a few have occurred in the U.S. without travel history to Africa. While treatments are lacking, a vaccine is available for mpox.

Additionally, Oropouche virus, transmitted by mosquitoes and biting midges, is expanding its reach across the Americas. Although typically causing mild, short-lived illness, its potential for wider spread and recurrence is noted. Other viruses like chikungunya, measles, and HIV also pose risks in 2026 due to factors like declining vaccination rates and disrupted aid.