Dr. Katelyn Jetelina didn’t intend to become a global voice during the pandemic, but what started as a newsletter to her students and colleagues has become a worldwide resource for millions.
Jetelina is a California native and assistant professor of epidemiology, human genetics, and environmental sciences at the University of Texas Health Science at Houston’s School of Public Health, which has a campus in Dallas. Her Substack newsletter, “Your Local Epidemiologist,” now reaches 125 million people in 150 countries (it is actively translated into several languages) worldwide, with public health information focused on the spread of COVID-19.
During the innocent and early days of the pandemic in 2019, she began closely following the spread of COVID-19, creating her own spreadsheets before every county, state, and country had a dashboard to display the spread of the virus. Her Dean approached her at UT Health Houston to send a newsletter to colleagues and students about what was then a virus impacting Italy and other places worldwide. A student asked if she could share the information on Facebook. She signed each missive “Your Local Epidemiologist.”
Her posts were very data-driven in the early days, pulling data from the World Health Organization and analyzing it in excel. As teams developed across the world, she would translate published data for her readers, helping them understand what it all meant. That led to discussions about behavior connected to the virus and vaccines and variants. The most recent posts include a series on the impact of Long COVID-19. “The content has ebbed and flowed just like the pandemic has ebbed and flowed,” she says.
As one might expect with an issue that has become so politicized, Jetelina gets plenty of positive and negative feedback from her readers. In 2021, anti-vaxxers hacked the Facebook page where she originally posted, so she moved her primary communication mode to Substack, though she copies the content to her social media sites as well. At times, she is inundated with Facebook messages and emails from the Substack (including at least one death threat). Still, she takes time to answer them because she knows the interactions provide crucial information. “The bidirectional conversations I have with followers is incredibly important for this scientific communication,” she says.
Most of the feedback she receives has been positive, she says. She remembers one touching email she received saying the newsletter helped a woman convince her elderly father to be vaccinated, even though he had never received any other vaccines.
Her most popular posts are the ones that explain how things work—describing how to do an antigen test and how it works, walking through the steps of a clinical trial, or the difference between the different vaccines. For Jetelina, it isn’t about telling people what to do but giving them information to make choices based on science rather than fear and misinformation. “I’m trying to equip people with the data to make their own evidence-based decisions because everyone’s on such a different risk tolerance spectrum.”
She takes great pains to separate science from politics, and a recent survey of her readers found that they come from a diverse political spectrum. She hasn’t been afraid to disagree with the authorities. She recalls that she was very vocally against the CDC advice that said unvaccinated people didn’t need to wear masks before the delta and omicron surges last year. “That’s how you break echo chambers,” she says. “Science isn’t supposed to infiltrate them. It’s supposed to break them. That’s been something I’ve done very purposely throughout.”
The newsletter hasn’t been easy to pull off for a mother of two children with a full-time job. So while the rest of us parents are sitting and watching a show after we put our kids to bed, she is hard at work on her newsletter, ready to go out the next morning. But the sacrifice has been worth it for Jetelina, who is part of a surge in interest in public health as a profession. “It’s filling a gap that people didn’t have before to try and understand what was going on.”