‘The Big One’ Could Be Worse Than COVID, Warns Top Epidemiologist

COVID-19 rewired daily life and killed millions worldwide, and yet one of America’s best-known pandemic experts says it may have been only the warm-up. Epidemiologist Michael Osterholm argues the next outbreak could spread faster, hit harder, and disrupt more than we’re ready for. His 2025 book The Big One lays out a realistic “SARS-3” scenario and what past pandemics teach us about surviving it. The warning isn’t meant to panic people. It’s meant to wake systems up.

In The Big One, Osterholm and co-author Mark Olshaker describe a plausible future where a deadlier coronavirus emerges and circles the globe despite modern public-health tools. They’re not predicting a specific date or virus, but showing how quickly a “SARS-3” could overwhelm hospitals, economies, and everyday life if we repeat COVID-era mistakes. The point is to pressure-test reality before reality pressure-tests us.

What past pandemics show about how bad “worse than COVID” can get

Osterholm stresses that the damage wouldn’t stop at infection. A severe airborne pandemic could shatter global supply chains, causing shortages of food, medicine, and even mundane basics like soap, light bulbs, and fuel. COVID gave a preview of how fragile “just-in-time” systems are. A deadlier outbreak could push that fragility into full collapse, especially if multiple manufacturing hubs shut down at once.

A huge lesson from COVID, Osterholm says, is that national borders don’t stop airborne viruses. The U.S. relies heavily on generic drug manufacturing in China and India; countries that would be prime targets for rapid spread and factory closures. That creates a vulnerability that isn’t just about health, but national security. Rebuilding pharmaceutical capacity elsewhere would take subsidies and long planning, which is why he argues it must start before a crisis hits.

COVID’s worst outcomes skewed toward older and immunocompromised groups, but history warns not to expect that pattern again. In 1918, influenza killed huge numbers of healthy adults ages 18–40, partly due to immune overreactions like cytokine storms and respiratory failure. Osterholm’s point is blunt: a future virus could target very different bodies, and medicine is not prepared to treat tens of millions of severe respiratory cases at once.

The preparedness gaps Osterholm says we still haven’t fixed

One of Osterholm’s sharpest critiques is how rich countries hoarded vaccines during COVID while low- and middle-income nations waited. That wasn’t only unfair; it was risky. If large populations remain unprotected, the virus keeps spreading and mutating, and new variants return to threaten everyone. He argues future vaccine planning must include global manufacturing scale-up and distribution agreements, not last-minute charity.

The book pushes an uncomfortable idea: pandemic readiness requires building manufacturing capacity that sits idle most of the time. Without pre-funded “surge” capacity, the world loses precious months waiting for factories to catch up. Osterholm says international public-funding structures should pay for that extra capacity ahead of time, because speed is everything when exponential spread is already underway.

Even in a best-case future with effective antivirals, supplies would be limited early in a crisis. Osterholm argues we should decide priority groups now — in public, ethically, and transparently — rather than in panic when hospitals are overflowing. Health workers, elderly patients, essential workers, leaders: every group will have advocates. Planning those tradeoffs ahead of time may be the difference between organized response and chaos.

Osterholm says we’re less ready now than before COVID

After COVID, many expected preparedness to improve. Osterholm says the opposite is happening: public-health infrastructure has been weakened, trust in institutions has eroded, and political fights keep drowning out science. That makes the next outbreak more dangerous by default. His argument isn’t that catastrophe is guaranteed, it’s that complacency makes catastrophe more likely.

The Big One isn’t a prophecy; it’s a stress test. Osterholm’s core message is that pandemics are inevitable, but disaster isn’t. If supply chains are reinforced, vaccine capacity is global, and ethical decisions are made before panic hits. COVID showed what happens when the world reacts late and separately. The next question is whether we’ll treat that experience as a warning shot… or a lesson learned too slowly. What do you think we still haven’t learned?