Social distancing and vaccines saved 800,000 lives during COVID-19, but at a high cost

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A new study from CU Boulder and UCLA reveals that changing people’s behavior, like social distancing and wearing masks, along with vaccines, saved roughly 800,000 lives in the U.S. during the COVID-19 pandemic. However, these measures came with significant economic, social, and human costs.

The research, published in the Brookings Papers on Economic Activity, shows that while behavior changes can be very effective in slowing the spread of a dangerous virus, they also have downsides.

The study’s authors suggest that having better infrastructure for public health data could reduce these costs in future pandemics.

The Power of Vaccines and Behavior Change

Stephen Kissler, a computer science assistant professor at CU Boulder, and Andrew Atkeson, an economics professor at UCLA, worked together to answer a crucial question: How many lives were saved by behavioral changes and vaccines?

Using national data on infections and vaccinations from February 2020 to February 2024, they used computer models to simulate the pandemic under different scenarios. They found that vaccines and behavior changes were closely linked and essential for saving lives.

Without vaccines, people changing their behavior would have only delayed infections, leading to a high death rate eventually. Without behavioral changes, vaccines would have come too late to save lives. Thanks to these combined efforts, 68% of Americans were vaccinated before getting infected, reducing their risk of dying from COVID-19.

The study estimated that without these interventions, 1.98 million people in the U.S. would have died from COVID-19, compared to the 1.18 million who did die. The pandemic would have spread rapidly, killing 60,000 people per day at its peak.

Lessons Learned and Future Preparedness

The study also found that the slowdown in vaccine uptake during the second half of 2021, as the virus mutated, led to an additional 273,000 preventable deaths from the Delta and Omicron variants. This highlighted the importance of maintaining high vaccination rates.

Kissler and Atkeson were surprised by the significant impact of behavior changes, noting that pre-pandemic studies underestimated their effectiveness. However, they worry that in future pandemics, people might be less willing to adopt these measures, thinking they overreacted during COVID-19.

The researchers emphasized the need for better public health data infrastructure to guide targeted interventions. They pointed to the CDC’s Center for Forecasting and Outbreak Analytics, which is developing a system similar to the National Weather Service to provide timely forecasts on virus spread and effective measures.

The recent Mpox outbreak, which was quickly contained with targeted interventions and vaccines, shows the potential of using detailed data to manage pandemics more effectively. By understanding how different communities respond and what measures work best, future pandemics can be managed without broad and costly shutdowns.

Kissler concluded, “If we have more detailed, timely data, we can target interventions better, so we don’t have to just stop everything.”