As the world steps into 2026, the specter of viral threats looms large, with experts closely monitoring several viruses that could pose significant risks. Patrick Jackson, an infectious diseases physician and researcher at the University of Virginia, highlights the evolving nature of viruses and the factors contributing to their spread. A warming climate, increased human mobility, and a growing global population are creating new opportunities for viruses to thrive and travel across the globe.
Influenza A: On the Brink of a Pandemic
Influenza A remains a perennial threat due to its ability to infect a wide range of animals and mutate rapidly. The H1N1 subtype, responsible for the 2009 pandemic that claimed over 280,000 lives in its first year, continues to circulate today. Recently, the highly pathogenic avian influenza H5N1, or bird flu, has garnered attention. Initially detected in humans in southern China in 1997, it spread worldwide with the help of wild birds.
In 2024, H5N1 made its way to dairy cattle in the U.S., establishing itself in several herds. This crossover from birds to mammals raises concerns about potential human adaptation. Studies suggest numerous cow-to-human transmissions have already occurred. Scientists are vigilant for signs of H5N1 evolving to enable human-to-human transmission, a critical step toward a new influenza pandemic. Current influenza vaccines likely offer little protection against H5N1, prompting efforts to develop effective vaccines.
Mpox: A Global Concern
Formerly known as monkeypox, the mpox virus was first identified in the 1950s. Although primarily infecting rodents, it occasionally crosses over to humans. Mpox is related to smallpox and causes fever and a painful rash. Vaccines exist, but treatments remain elusive. A global outbreak of clade II mpox in 2022 spread to over 100 countries, driven by human-to-human transmission through close contact, often sexual.
While mpox cases have declined since the 2022 outbreak, clade II mpox is now globally established. Reports of clade I mpox cases have increased in central Africa since 2024, with four cases occurring in the U.S. among individuals with no travel history to Africa. The evolution of mpox outbreaks in 2026 remains uncertain.
Oropouche Virus: Insect-Borne and Expanding
First identified in the 1950s on Trinidad, the Oropouche virus is transmitted by mosquitoes and biting midges. Symptoms include fever, headache, and muscle aches, with some patients experiencing prolonged weakness. The virus can recur after initial recovery, and no specific treatments or vaccines are available.
Historically confined to the Amazon, Oropouche cases have spread to a broader area of South America, Central America, and the Caribbean since the early 2000s. Infections in the U.S. are typically among travelers returning from abroad. In 2026, Oropouche outbreaks may continue to affect travelers in the Americas, with the virus potentially expanding its range, given the presence of its vectors in North and South America.
Emerging Viral Threats
Beyond these known threats, other viruses pose risks in 2026. Chikungunya virus outbreaks continue globally, prompting some travelers to consider vaccination. Measles cases are rising in the U.S. and worldwide amid declining vaccination rates. HIV, despite effective treatments, faces a potential resurgence due to disruptions in international aid.
New, undiscovered viruses may emerge as humans disrupt ecosystems and travel globally. The interconnectedness of people, animals, and the environment underscores the need for vigilance against known and emerging viral threats. Developing new vaccines and treatments remains crucial for global safety.
This article is republished from The Conversation under a Creative Commons license. Read the original article by Patrick Jackson, Assistant Professor of Infectious Diseases, University of Virginia.
