There is no officially declared new pandemic as of early 2026. No pathogen currently meets the World Health Organization’s threshold for a Public Health Emergency of International Concern at pandemic scale. But several infectious disease threats are being closely watched, and the one generating the most attention is H5N1 bird flu, which has been spreading among animals and occasionally jumping to humans.
Why H5N1 Bird Flu Is the Top Concern
H5N1 avian influenza has circulated in birds for decades, but its recent spread into dairy cattle, poultry farms, and sporadic human cases has put it at the center of pandemic preparedness discussions. The CDC reports 71 human cases and 2 deaths in the United States. The current public health risk is rated as low, and there is no known person-to-person spread at this time.
That last detail is the critical one. A virus needs to spread efficiently between people to cause a pandemic, and H5N1 hasn’t acquired that ability yet. Nearly all human cases have been linked to direct contact with infected animals, particularly among farmworkers. The concern isn’t what the virus is doing now. It’s what it could do if it mutates in a way that allows easy airborne transmission between humans, something influenza viruses have done before.
How Bird Flu Symptoms Differ From Regular Flu
The most distinctive symptom in recent U.S. cases has been eye redness, not the cough and fever most people associate with the flu. Conjunctivitis (red, irritated eyes) can appear just one to two days after exposure, while respiratory symptoms like cough, sore throat, and fever typically take about three days to develop, with a range of two to seven days.
Mild cases look similar to seasonal flu: low-grade fever, body aches, headache, fatigue, runny nose. What sets moderate to severe bird flu apart is how quickly it can escalate. Warning signs include high fever that limits normal activity, shortness of breath, altered consciousness, and seizures. Diarrhea, nausea, and vomiting are less common but possible. The period of contagiousness for mild illness isn’t well understood but is thought to be similar to seasonal flu.
Vaccine Readiness for a Bird Flu Pandemic
Governments aren’t waiting for a pandemic to start before preparing vaccines. The U.S. maintains a National Pre-pandemic Influenza Vaccine Stockpile that stores the raw building blocks of a vaccine: bulk antigens (the component that trains your immune system to recognize the virus) and adjuvants (ingredients that boost the immune response so less antigen is needed per dose). The stockpile holds enough material to rapidly produce doses for critical care workers and high-risk populations in the early phases of a response, with the capacity to manufacture millions of additional doses within weeks.
This approach reflects a lesson from COVID-19. Rather than starting from scratch, the strategy is to have a head start so vaccine production can ramp up quickly if the virus changes in a dangerous way.
Other Threats on the Radar
Mpox
The global mpox outbreak, caused by the clade IIb strain, has infected more than 100,000 people across 122 countries, including 115 where the virus had never been reported before. Clade II mpox is still circulating at low levels. A separate concern is clade I mpox, which includes subclades Ia and Ib and has caused outbreaks in parts of Central and East Africa. Clade I infections tend to be more severe, though both strains are being monitored.
Marburg Virus
Marburg virus disease, a relative of Ebola, resurfaced in Rwanda in September 2024 (the country’s first outbreak) and in Tanzania in January 2025. The average fatality rate across past outbreaks is around 50%, though it has ranged from 24% to 88% depending on the quality and speed of medical care. Marburg spreads through direct contact with the blood or bodily fluids of infected people, not through the air, which limits its pandemic potential. It causes severe, often fatal illness but tends to burn through small populations rather than spreading globally.
Disease X
You may have seen references to “Disease X” in headlines. This isn’t an actual pathogen. It’s a placeholder the WHO uses on its priority research list to represent the possibility that the next major epidemic could come from a virus nobody has identified yet. The concept exists to push governments and researchers to invest in flexible tools, like rapid vaccine platforms and broad-spectrum antivirals, that could be adapted quickly when a novel threat emerges.
The Global Pandemic Agreement
In the background of all these threats, countries have been negotiating a global pandemic agreement through the WHO. The agreement was adopted in principle, but key details are still being worked out, including a system for sharing pathogen samples and ensuring that vaccines, treatments, and diagnostic tools are distributed fairly across rich and poor countries alike. The agreement will officially take effect 30 days after 60 countries ratify it through their own domestic processes.
The agreement covers disease surveillance, health workforce protections, research coordination, local manufacturing capacity, and a global supply chain network for distributing health products during a crisis. It also establishes a financial mechanism to help lower-income countries build pandemic preparedness. One point that has been politically contentious: the agreement explicitly states it does not give the WHO authority to impose lockdowns or vaccine mandates on any country. Those decisions remain with national governments.
What This Means Right Now
The honest answer to “what is the new pandemic” is that there isn’t one yet. H5N1 is the threat that most concerns epidemiologists because influenza viruses are uniquely capable of rapid mutation and global spread, and this particular strain has a foothold in animal populations worldwide. But “concerning” and “imminent” are not the same thing. The virus would need to gain the ability to spread efficiently from person to person, and surveillance systems are specifically designed to catch that shift early. For now, the practical risk to most people remains low.