Welcome to Season 2 of Public Health On Call, a podcast from the Johns Hopkins Bloomberg School of Public Health.

I'm Joshua Sharfstein, Vice Dean for Public Health Practice and Community Engagement,

and a former secretary of Maryland's Health Department.

Our goal is to bring scientific evidence and experience to the public health news of the day

through informative interviews with scientists, community leaders, policy experts, public health

officials, clinicians, and more. If you have ideas or questions for us to cover, please email us at

Public Health Question at jhhhu.edu. That's public health question at jhhu.edu for future podcast

episodes. It's a Friday Q&A episode where we track down an expert to answer listener questions. A brief note,

the podcast receives some emails asking for individual health recommendations. We cannot

diagnose or offer health advice to individuals. It's best to call your doctor or your local

health department with specific questions. Now to the Q&A.

Our respondent today is the remarkable Dr. Amesh Adalja,

senior scholar at the Center for Health Security.

He's a physician trained in internal medicine,

emergency medicine, infectious disease, and critical care.

Let's listen.

Dr. Adalja, thank you so much for joining me to answer some of our listener questions.

You ready to jump in?

Sure.

First question, what do we know at this point about reinfection?

So there have been a couple of well-documented re-infections.

But the bottom line thing to remember about reinfections is that think about how many millions of infections we've had around the globe and that there's only four reinfections that we're talking about. So this isn't the normal thing to expect. We know with most infectious diseases, once you get infected and you clear the infection, you have this period where you can't be re-infected. And I think that's the

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