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When Dr. Shan Woo Liu was a girl, her parents kept a copy of “Plague Fighter” on their family’s coffee table. The book told the story of her great grandfather, Dr. Wu Lien-teh, and his essential role in eradicating a pneumonic plague in 1911 China. His invention of protective face masks would be the predecessor of today’s N95 mask.
A century later, Liu fought against the COVID-19 pandemic, as an emergency medicine physician at Massachusetts General Hospital. In response to what she saw as a limited representation of Asian heroes in children’s literature, Liu began another mission, this time, bolstered by the story of her great-grandfather. In her new picture book, “Masked Hero: How Wu Lien-teh Invented the Mask That Ended an Epidemic,” Liu and her daughter, Kaili Liu Gormley, share Wu’s fascinating history — from his struggle against disease and discrimination to his ultimate triumph as an innovator. (His impressive career later earned him a Nobel Prize nomination and a Google Doodle.)
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The book was published this month by MIT Kids Press, and Liu and her daughter will participate in a reading at Brookline Booksmith on Sunday, Oct. 22, as part of the book store’s Picture Book Hour! series.

How did being a doctor shape the way you approached this book?
When you write in medicine, you have to be so strict in not overstating anything. This [book has] a completely different audience, so I had to change that mind-set and make digestible lessons for kids to take on. I wrote it in August and September of 2020. That draft was 700 words and I think every one of those words got changed except for his name. Every word is important and was scrutinized.
Tell me about the origins of the idea. It was your coauthor who began the writing process first thanks to a school project, is that correct?
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It was May of 2020 and everything was shut down, so I put my daughter in an online class. She had a nonfiction writing assignment, and at that time, there was still a lot of debate about masks. So I told her, “We should write about your great-great-grandfather, because he’s largely the reason why they use masks in Asia.” Then, over the summer, we read and read and there’s just a lack of representation of East Asian [characters] in books. It was this very maternal instinct to say, “This is what I can do for you and your brother. I want to do something to make you proud of who you are and where you’re from and your racial origins,” and that’s how the whole story started.
Your great-grandfather experienced industry skepticism, racism, and a fatal virus. He was able to figure out not only what was going on, but came up with a solution we rely on to this day. Were there parallels between what he faced then and what doctors today faced with COVID-19, particularly in the early days of the pandemic?
It felt like there were for me. Fast-forward 100 years as I’m working in the emergency department and it was fascinating to be on the front lines for COVID, but it was still terrifying to be presented by something that was completely unknown and mysterious. I have such respect for my great-grandfather, who had no idea what he was walking into, and faced even scarier situations than I did. But I had a small inkling of what he felt 100 years later. It was ironic to be a descendant of his and really depend on something he had a role in making. There’s a tremendous amount of pride.
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Parents often use picture books to open up conversations with kids about bigger topics and feelings. What are some of the discussions or takeaways you hope this book inspires?
The main message for younger kids is, “How can I help?” or “What role do I play in public health?” And for older kids, it’s a little bit more about representation, and [that] heroes can come in all different sizes and races and genders. Being brave when you’re called to step up and do things is scary. Even if you have the skill set, it doesn’t mean you’re not scared. [It’s about] determination and being brave in acknowledging that there are fears.
Why is now the right time to speak to kids not only about masks, but the larger themes of your great-grandfather’s experiences, such as racism, courage, and perseverance?
We are still seeing spikes in COVID … so, I still believe if you are at risk and vulnerable, you should get vaccinated and wear a mask in crowded situations. It’s not only about COVID. None of us want to have the flu or RSV or any other respiratory [illness], so I still think that wearing a mask is just a good public health measure. And, as far as representation, we have a lot of work to do to make everyone feel respected and honored. This is true among many, many stories that need to be told, so that when kids are growing up they have a huge, diverse array of people that they can call heroes.
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Your daughter, Kaili, was only 6 when you wrote this book. Did she enjoy the writing process and will you two coauthor in the future?
She was my consultant and she’s still my consultant! When we give book talks, she tells me, “I don’t want to go to a book talk and feel like I’m in school.” She reminds me to make it more fun and less teaching. She is more graphic design- and visually-oriented, so she had a hand in deciding choices of words and visual editing. And now, she’s been really helpful in how to reach kids and what themes they can appreciate. It’s also teaching her that you have power, and we all have stories. And, if you’re a kid and have stories, you can be a storyteller, too.
Dr. Shan Woo Liu and Kaili Liu Gormley at Brookline Booksmith, Oct. 22 at 10:30 a.m., 279 Harvard St., Brookline. Free. Registration requested, brooklinebooksmith.com.
Interview was edited and condensed.
Jennifer Fitzgerald is a writer from Los Angeles. She can be followed on X at @JenMaryFitz.