Learning from COVID-19

UMD Biology Professor Joshua Weitz shares insights from the pandemic in a new book.

In December 2021, physicist-turned-biologist Joshua Weitz was on a pandemic-delayed research sabbatical at the Institute of Biology of the École Normale Supériere in Paris with his family when COVID-19 unexpectedly hit home.

“I brought my daughter to a local pharmacy to get her a rapid COVID test as a precaution before going to a gathering. At the time, she felt totally fine,” Weitz recalled. “Moments after we left the pharmacy, the pharmacist ran out of the store yelling her name, and I knew immediately what that meant: she had tested positive for COVID.”

Weitz, then a professor at the Georgia Institute of Technology and a leading researcher in quantitative viral dynamics, had spent two years collaborating with scientists from around the world, trying to decipher the spread of COVID-19. In 2020, he led a highly successful rapid-response risk assessment and asymptomatic testing effort at Georgia Tech that reached more than 16 million people. But in that moment, outside a pharmacy in Paris, Weitz began to see COVID-19 from a different perspective.

“This moment personalized what I had been working on for two years — asymptomatic transmission— the fact that many people could get infected without realizing it, which leads to secondary spread, including the potential for severe and even fatal infections,” Weitz explained. “I began to grow worried that we weren’t going to learn the lessons that we needed to learn and communicate them moving forward.”

From the pandemic to “Asymptomatic”

Fast forward three years and a lot has changed. Weitz is now a professor in the Department of Biology at the University of Maryland, where he holds the Clark Leadership Chair in Data Analytics and recently joined the University of Maryland Institute for Health Computing. Weitz’s groundbreaking research and his experience with the COVID-19 pandemic inspired him to write a new book, “Asymptomatic: The Silent Spread of COVID-19 and the Future of Pandemics,” which will be released on October 22, 2024.

An award-winning author, Weitz has written textbooks and more than 170 peer-reviewed papers for scientific journals. But he says “Asymptomatic” is not just for scientists, it’s for anyone who wants to gain a better understanding of the pandemic that claimed millions of lives and changed everyday life in ways we could never have imagined.

“This book is for anyone interested in science, health, and society,” Weitz said. “My hope is that Asymptomatic will resonate with readers interested in epidemics, policymaking, and public health who want to understand something essential and often misunderstood about a disease that transformed our lives.”

And the book has a powerful message to share.

“The key message is this: COVID-19 has shown that diseases that don’t necessarily cause as much individual harm can cause extreme, what I would call catastrophic societal harm, especially when those diseases can transmit even in the absence of symptoms,” Weitz said. “This is the core piece of why COVID-19 was so severe—you couldn’t use symptom checkers to stop it. The disease was going outside of our conventional approaches to detection and that makes outbreaks hard to stop.”

Deciphering the danger of silent spread

Part 1 of Weitz’s book tells the suspenseful and often frightening story of COVID-19, a virus that could be mild or asymptomatic for so many but dangerous, even deadly, for countless others—and why it was so difficult to contain. Studies showed that many, perhaps even half of those infected with COVID-19 in 2020 had such mild infections they never knew they had the virus, and because of that, they might be less likely to take precautions to avoid infecting others.

“This idea that there are people who feel fine, don’t take precautions, go out and interact with others while transmitting this infection can lead to rapid, uncontrolled spread, “ Weitz explained. “It’s the thing that shows up in horror movies—you don’t know that this person’s shedding viruses and you’re near them and you get infected.”

With a narrative that meshes the science of viral infections with the real-world challenges of responding to a rapidly changing pandemic threat, Weitz’s book recalls the sometimes misguided predictions, misconceptions, superspreader events and lockdowns that unfolded during the pandemic—and what scientists were learning about the silent and surprising ways that COVID was able to spread.

“In early 2020, we knew that infected individuals could often exhibit symptoms before the person that infected them – the precise opposite of conventional expectations. This is bad news for pandemic control because individuals can and do infect others before they recognize they are sick,” Weitz said. “The book reveals the science and public health consequences of small details that are critical to understand COVID-19 and to classify future pandemic risk.”

Lessons for the future

In Part 2 of “Asymptomatic,” Weitz explains how our understanding of what went right—and wrong—in the fight against COVID-19 can help us prevent future pandemics—even if, for some, those details might already be lost in the fog of memory.

“I think there are some key details of the pandemic that we, the ‘insiders’ working on pandemic response, saw as being quite disturbing early on, but for the general public, probably just disappeared into noise,” Weitz noted. “For me, these are critical take-homes that are signals of what the public and public health decision-makers should prioritize moving forward.”

Weitz explains how a diverse repertoire of approaches to combat asymptomatic transmission including real-time risk assessment, easier access to testing, improved indoor air quality, targeted masking, and updated vaccines can inform smarter policies to protect the population in the future and fight the silent spread of infection that made COVID-19 so devastating.

“The book explores how COVID-19’s asymptomatic spread led to catastrophic impacts and looks forward at how we can prevent disease outbreaks in the future,” Weitz said. “How do we change the landscape of public health prevention to focus on reducing transmission, not just treating symptoms after they occur?”

Continuing a 20-year mission

Weitz’s research and his new book on the COVID pandemic continue to advance a scientific mission that has inspired and motivated him for more than two decades—elevating our understanding of how viruses shape human and environmental health and the fate of our planet. If we can learn from our experience with the COVID-19 pandemic, Weitz believes we have a better chance of preventing the next one.

“My hope is that the book helps identify essential lessons we should learn from COVID-19,” Weitz said. “We need to start building the infrastructure now. If not, we could be back in the same place all over again when the next disease of pandemic potential hits.”