The sound of science

In May 2022, Joshua Sharfstein sat down for a heart-to-heart conversation about COVID-19 with his 78-year-old mother, Margaret. Sharfstein, a Distinguished Professor of the Practice at the Bloomberg School of Public Health, had once been a Baltimore City health commissioner. His mother, a retired pediatrician, was also no stranger to medical discussions. And yet, the topic that day—the months of loneliness, fear, and confusion resulting from the ongoing pandemic—wasn't an easy one to broach.

His mother recalled the day, early in the outbreak, when she saw a news story about elderly patients dying at an alarming rate. Those over 65 were far more susceptible to the virus, the CDC warned. "Up until that time, I never considered myself old. I never thought about my numerical age but was just happy going about my regular life," she told her son. "That was a brand-new feeling."

Sharfstein had encouraged her to stay home and avoid public spaces. He'd wanted to protect her. "I wasn't always supportive of what you wanted to do," Sharfstein admitted.

"That is correct. I had a nickname for you. It was Dr. No."

Their 14-minute chat was frank, vulnerable, and often humorous: the kind of intimate exchange that many of us wish we could have with our loved ones about sensitive health subjects. Only this conversation was being recorded, and when it aired as a special Mother's Day episode of the Public Health on Call podcast, tens of thousands of listeners from around the globe were privy to a poignant moment between mother and son.

The Public Health on Call podcast, a production of the Bloomberg School and co-hosted by Sharfstein, Lindsay Smith Rogers, and Stephanie Desmon, first aired on March 2, 2020, just as the global pandemic swept the globe. It became an instantaneous breakout success. Five years on, the show has nearly 11.5 million downloads, a bevy of awards, and an audience of over 100,000 dedicated listeners on its two main platforms, Spotify and Apple. With well over 850 episodes, the podcast has found a listenership hungry for reliable scientific evidence and expertise capable of illuminating critical issues, while also humanizing public health and making it accessible. The podcast has offered expert takes on everything from reducing gun violence and the rise of avian flu to new cancer screening tools and the latest facts about sunscreen. At a time when misinformation and myth run rampant, the podcast has emerged as a powerful platform for evidence-based facts and insightful conversations.

The idea for Public Health on Call arose in the winter of 2020 in the school's hallways. Rumblings of a new and dangerous disease, the as-yet named coronavirus, had grown with the number of global patient cases. "Things in the public health world were pointing to this becoming a significant event," says Lindsay Smith Rogers, director of content strategy at BSPH and a producer and co-host of the show.

Sharfstein, meanwhile, was having conversations with experts around the school, including virologists, epidemiologists, and especially staff at the Johns Hopkins Center for Health Security, who work to protect people from epidemics and pandemics. "They were saying: 'This is it. The alarm bells are ringing. This is the thing we've been afraid of,'" Rogers remembers.

Sharfstein thought BSPH should find a way to broadcast these private conversations and share the informed insights of their experts more widely. The public was already being inundated with a flood of conflicting and confusing information about the virus. The news media struggled to cover a rapidly changing health crisis, and social media compounded the proliferation of speculation and falsehood. It left many overwhelmed and deeply confused, and it led to what some called an "infodemic," where misinformation traveled faster than actual science and common sense. Sharfstein, who has experience podcasting, suggested that Johns Hopkins should create a show that could unpack information in real time. Only, BSPH had never done a podcast before.

Sharfstein took the idea to Lymari Morales, associate dean for communications and marketing, who immediately saw the potential. She suggested that the podcast could be more than just a rapid response to COVID-19. "We all knew early on that we wanted it to work for the long term, too," Morales says. "We thought we could start with COVID and then extend it to other topics. We could call up a public health expert whenever there's a topic in the news and get their knowledge quickly."

Around this time, Johns Hopkins colleagues launched the COVID-19 digital tracker, a map that illustrated the spread of the disease. The world had questions, and increasingly, they were turning to Hopkins for answers. "People here were working on the frontlines of the pandemic," Sharfstein says. "We wanted to have them speak on topics that people would be interested in and benefit from hearing about."

By late February 2020, just as the first non-travel-related case of COVID-19 had been confirmed in California, the team began planning their content. They decided early that the "voice" of the podcast should be interesting and timely perspectives within the world of public health. Each episode would tackle a succinct question, with the host interviewing one person who could offer listeners clarity on the topic. "This was different from a lot of podcasts that were exploring very controversial ideas and were meant to grab attention," Rogers says. "There's a role for podcasts like that; it just wasn't our goal. We wanted our podcast to be reasonable conversations with thoughtful people."

A handful of BSPH staff figured out how to release the podcast on the fly. They signed up for a syndication account and learned the necessary components of a successful show. "We needed an intro, a title, a summary, show notes, credits. We needed music," Rogers says. Sharfstein started by recording guests on a hand-held recorder.

At the same time, Sharfstein had been helping to plan a webinar symposium, where experts, including Sharfstein, could answer pressing questions about the virus. More than 147,000 viewed it online. The audio from the webinar became the first episode of Public Health on Call and was released the first week of March 2020. The podcast team simultaneously set up a public-facing email account, where people could send questions. Within days they had thousands of emails. "It took three of us to triage the email inbox," Rogers says.

One of the first experts Sharfstein featured on the podcast was Hopkins virologist Andrew Pekosz. Sharfstein began by asking basic questions: What's a virologist? What happens in a virus lab? Pekosz described the basic science of a respiratory virus and then gave listeners a baseline understanding of what was happening behind the scenes as scientists worked to understand what was then called SARS-CoV-2. He explained what was known and not yet understood. Hundreds of scientific articles about the virus were being posted, yet few media professionals had the capacity to weed through them all, let alone explain the content. Scientific facts and medical knowledge weren't getting to the public. The podcast aimed to bridge that gap.

"Almost at an hourly basis, something new was coming down the pipeline, and trying to figure out what was correct, what was valid, and what was speculation was a challenge," Pekosz says today. "In those early days of the pandemic, too often people were saying: 'We don't know.' And while that may have been true, that didn't speak to the research people were conducting, and it didn't clarify what our best guesses were for what was going on with the outbreak."

The format of the podcast—around 15 minutes—is short and easy to digest in one sitting, but it also meant that Pekosz had time to go into more detail than he could during a traditional news interview. Sharfstein endeavored to keep that interview conversational. Near the end of the show, Sharfstein asked Pekosz a personal question: He wondered what he was most concerned about as a virologist. "I rarely get those kinds of questions in any significant way from formal news media," Pekosz says. "This is something Public Health on Call is really good at doing. Having a real conversation. I'm not just an investigator who was responding to the pandemic. I'm a person with a family who had to deal with it, too, and that comes through in this podcast. They keep to that wonderful, sweet spot where you're learning things, but you're not getting information that's too detailed, too much in the weeds."

The podcast managed to feel both polished and accessible at the same time. Listener response indicated this was a successful combination. "As soon as we were putting [episodes] up, we could see the metrics," Rogers says. "It was incredible. At the same time, our colleagues with the map tracker were seeing incredible traffic there, too."

They also began running a Friday Q&A episode where they could address listener queries with experts like Crystal Watson of the Center for Health Security. One week a listener wanted to know if masks got less effective the longer they were worn. Another wondered about the scientific evidence on chloroquine use, while a new mother questioned whether the virus, or any antibodies she might have to the virus, could spread through breastmilk.

Sharfstein put together daily episodes as quickly as he could, but it was evident that he needed help. He asked Stephanie Desmon, director of public relations and communications for the Johns Hopkins Center for Communication Programs, to co-host. Desmon came to Hopkins after a career as an award-winning journalist covering health care, and she'd known Sharfstein since his years as a city health commissioner. "I remember Josh asked me if I wanted to do a podcast with him and I said, 'How are you going to put out a daily podcast about COVID? How is it possible that there will be enough to talk about every day?'"

In fact, starting in May 2020, they began putting out at least two episodes a day, a pace they kept up for a year. Together, and with the help of Rogers as producer and co-host, they built a show that featured myriad perspectives from inside and outside Johns Hopkins. They interviewed health officers, elected and community leaders, physicians, patients, and foreign officials. A physician from China talked about what he was seeing in patients, a mayor from Nebraska confessed how challenging it was to balance public safety with human need during the lockdown. By the end of the first year, they had interviewed 70 faculty members from across the university. Moreover, they gave a voice to the experiences of people at the front lines of a public health emergency. "We were all living this. COVID was happening to us as well," Desmon says. "I'm a former journalist and a mom, and I came to the podcast with those two perspectives. We felt the same urgency that everybody else felt. It was this feeling to me that we could humanize all these questions and hopefully try to assuage some fears." When Desmon interviewed two public health officials who were also moms, for instance, she asked them: "How are you celebrating Halloween? What are you doing to keep safety in mind while leading a normal life? What are the trade-offs?"

Within weeks of being on the podcast, Desmon became a mini celebrity in her neighborhood. "I went on a walk and ran into a friend of mine, and she said, 'I'm listening to you right now!'"

Pekosz, a repeat guest on the show, had his name recognized when picking up a takeout order. "People were definitely listening," he says. Part of the show's appeal, Pekosz believes, is that it consistently aims to offer facts as well as delve into the messier gray areas. "It's so much easier to cast fear and doubt into a person than it is to reassure them," Pekosz says. "A person who is spreading misinformation so often speaks in absolute measures."

The team rounded out their coverage by offering arts, culture, and book club conversations. "A lot of the reaction to COVID—and a lot of the reaction that we see now to science—it's not new. It's happened before," Rogers says. "A lot of it is rooted in fear. It's rooted in people not getting their needs met. We can bring context to that." They've done podcasts about Camus' The Plague and brought in artists, writers, historians, and psychologists to offer the long view of the human relationship with public health.

Public Health on Call proved to be an incredibly effective form of communication during the COVID-19 pandemic, but it continued to attract new audiences as it expanded its coverage. By June 2021, the team adjusted the frequency of Public Health on Call to three episodes per week plus occasional bonus episodes for breaking news. They branched out, as planned, and featured episodes on gun violence, addiction, and environmental health concerns. "I believe strongly in the ability of translating complicated things to people that they can really use. Real science and real context," Desmon says.

In 2025, a podcast offering reasoned, researched, and thoughtful public health discourse is more vital than ever. "We're in a moment where public health is in the spotlight again," Rogers says, as bird flu is on the rise, measles spreads in Texas, and climate change increases the ferocity and regularity of natural disasters, from wildfires to flooding. Today, the podcast has a staff of 12 and they continue to serve as a rapid response team to breaking news. They've increased their frequency to four episodes a week to keep pace. With the new White House administration's spate of executive orders in January, they unpacked each order and what those meant for public health. As Robert F. Kennedy Jr. testified before the Senate for the role of secretary of health and human services in February, the podcast ran a series of shows on vaccines. And they had bestselling author John Green on the show to discuss his new nonfiction book on the history of tuberculosis.

Episodes remain free and easy to access, and always clock in under 20 minutes. Listeners can take them in any time, on their schedule, and without a need for concentrated focus. "Podcasts fill that need, where you pop them on and you learn something while you're doing something else. You listen while you drive, make dinner, take a walk. You can put the podcast on and enhance what you get out of a block of time," Pekosz says.

Five years in, and Sharfstein, Desmon, and Rogers have become familiar voices to audiences, with each bringing a unique perspective to the topics they cover. They've become a bit like the NPR of public health—a consistent source of timely news and information rooted in reliable sourcing. "There's a whole audience of people out there who care deeply about the collective public's health," Rogers says. "It goes well beyond COVID. And we've found that people are along for this ride."