Yes. Another pandemic is virtually certain. The question isn’t whether it will happen but when, and how severe it will be. A 2021 analysis published in the Proceedings of the National Academy of Sciences estimated that the probability of experiencing a pandemic on the scale of COVID-19 within any person’s lifetime is roughly 38%, and that figure may double in the coming decades as environmental conditions shift in favor of new diseases jumping from animals to humans.
What the Historical Pattern Shows
Major outbreaks have been accelerating over the past century. The Spanish flu struck in 1918, and the next comparable global threat didn’t arrive until the Asian flu in 1957, a gap of nearly four decades. But the intervals have been shrinking. HIV/AIDS emerged in 1981, SARS in 2002, the H1N1 swine flu in 2009, Ebola in 2014, and COVID-19 in 2019. That last stretch saw three significant outbreaks in just ten years.
This isn’t coincidence. The conditions that produce pandemics are intensifying, not easing. More people live in closer contact with wildlife, more international flights connect cities every day, and the global population is larger and more urbanized than at any point in history. Each of these factors shortens the fuse between a localized animal virus and a worldwide crisis.
Why the Risk Is Growing
Most pandemics begin the same way: a pathogen that normally circulates in animals makes the jump to humans. This process, called zoonotic spillover, is driven by how much contact people have with wildlife. Deforestation, expanding agriculture, and urban sprawl are steadily eroding the ecological barriers that once kept human and animal populations separated. As those boundaries shrink, encounters between people and virus-carrying animals become more frequent.
Climate change compounds the problem. Warming temperatures push animal species into new territories, bringing their viruses with them and creating opportunities for transmission that didn’t previously exist. The PNAS analysis estimated that the yearly probability of an extreme epidemic could triple over the coming decades if disease emergence from animal reservoirs continues rising at its current pace. Under that scenario, the average gap between Spanish flu-scale events could fall to roughly 292 years, down from what was historically a much rarer occurrence.
There’s also a newer, less natural risk. Advances in synthetic biology have made it possible to engineer pathogens in ways that don’t occur in nature, including increasing how easily a microbe spreads or making it resistant to existing treatments. Researchers have already demonstrated the ability to synthesize viruses like horsepox in a lab, raising concerns that the same techniques could be used to reconstruct dangerous pathogens. The Biological Weapons Convention, signed by 183 countries, prohibits this kind of work, but it has no enforcement mechanism. And many researchers working with gene-editing tools now operate outside the oversight of any government funding body.
The Threats Being Watched Right Now
The World Health Organization maintains a list of priority diseases with pandemic potential. It includes COVID-19, Ebola, Marburg virus disease, MERS and SARS coronaviruses, Nipah virus, Lassa fever, Crimean-Congo hemorrhagic fever, Rift Valley fever, and Zika. The list also includes something called “Disease X,” a placeholder for the possibility that the next pandemic comes from a pathogen nobody has identified yet. That’s not a hypothetical scenario. COVID-19 was essentially Disease X when it first appeared in late 2019.
H5N1 bird flu is one of the most closely monitored threats right now. As of mid-2025, 71 human cases and 2 deaths have been reported in the United States since February 2024, with 26 infections reported globally between January and August 2025. The CDC currently rates the public health risk as low, and no person-to-person spread has been confirmed. But influenza viruses mutate rapidly, and the concern is that H5N1 could acquire the ability to spread efficiently between people. If that happens, the world would face a virus with a far higher fatality rate than COVID-19.
What’s Being Done to Prepare
The global response infrastructure is significantly better than it was before COVID-19, though still incomplete. One major initiative is the 100 Days Mission, a goal adopted by the G7 and G20 to have vaccines ready for emergency use within 100 days of identifying a new pandemic pathogen. The effort focuses on developing prototype vaccines for entire virus families in advance, so researchers can quickly adapt them when a specific threat emerges. Progress is real: the first Phase III trial for a chikungunya vaccine and the first human trials for a Nipah vaccine have already been completed under this framework, and several Lassa fever vaccine candidates are in advanced development.
On the diplomatic front, the World Health Assembly adopted the WHO Pandemic Agreement in May 2025. The agreement creates a system for countries to share pathogen samples and genomic data quickly while ensuring that vaccines and treatments are distributed more equitably than they were during COVID-19. It also establishes a global supply chain network for pandemic-related health products and a financial mechanism to help lower-income countries build their preparedness capacity. The agreement enters into force once 60 countries ratify it, a process that will take time as each nation works through its own legal requirements.
Prevention is also dramatically cheaper than response. The cost of COVID-19 to the U.S. economy alone was estimated at up to $16 trillion by the end of 2021. By comparison, the price tag for global pandemic prevention measures would be roughly 100 times less. Investments in wildlife surveillance, early detection systems, and rapid-response infrastructure represent a fraction of what a single pandemic costs in lives and economic damage.
What This Means in Practical Terms
The 38% lifetime probability figure is worth sitting with. It means that if you’re alive today, you have roughly a one-in-three chance of living through another pandemic comparable to COVID-19, on top of having already experienced one. And that estimate is based on current conditions. As deforestation continues and climate change accelerates, the odds go up.
None of this means the next pandemic will look like COVID-19. It could be milder or more severe, spread faster or slower, or come from a completely unexpected source. What the data consistently shows is that the underlying conditions producing new infectious diseases are worsening, and the pace of major outbreaks over the last several decades reflects that. The tools to respond are improving too, but a gap remains between what’s possible and what’s actually been built and funded. The next pandemic will test whether the lessons of COVID-19 translated into durable change or just temporary urgency.