President Donald Trump’s early morning tweet that he and the First Lady tested positive for COVID-19 stunned the nation and world. By mid-morning, media were reporting that the president was exhibiting mild cold-like symptoms and planned to quarantine himself in the White House. Other officials, including Vice President Mike Pence, have tested negative.

At 74 years old, Trump is in an age group with a much greater risk of experiencing complications from the disease. Colorado State University immunology expert Brian Geiss explains why.

Trump’s positive test also raises concerns over whether he’ll need to hand power over to Pence. Worth another read this morning is an article we published in 2018 – during another kind of crisis – that explains how the power of the president changes hands.

Also today:

Maggie Villiger

Senior Science + Technology Editor

Masking up is one way to cut down on risk of COVID-19 infection. Alex Brandon/Getty Images News via Getty Images

Older people like President Trump are at more risk from COVID-19 because of how the immune system ages

Brian Geiss, Colorado State University

Older coronavirus patients face grimmer outlooks. A virologist explains the aging-related changes in how immune systems work that are to blame.

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