A cascading number of European countries have halted distributing the AstraZeneca/Oxford Covid-19 vaccine over concerns about blood clotting. / The Associated Press

More than 17 million people have received the AZ vaccine. As of March 8, only 37 people subsequently developed blood clots. / Quartz

The EU's medicine regulator reiterates there is no indication that the AZ vaccine was the reason those blood clots formed. “While governments are pulling the plug, most scientists are rolling their eyes.” / BBC News, The Guardian

“Should You Be Concerned About Blood Clots, Bleeding and the AZ-Vaccine?” / The New York Times

Moderna begins studying its vaccine in children in the US and Canada. / The Wall Street Journal

A survey finds little difference in reluctance to take the coronavirus vaccine among Black and white people in the US. The truly reluctant: Republicans. / NPR, NBC News 

States with Democratic governors had higher death rates early in the pandemic—a trend that reversed by the Fourth of July. / NBC News

David Wallace-Wells: Why did rich countries initially get Covid so wrong? / New York Magazine

Helen Branswell: Vaccines are having a moment for the first time in decades. What if it's a reset? / STAT

Zeynep Tufekci: The falling hospitalization rate for Covid patients in the US is very encouraging. / Twitter

Neil Irwin: Seventeen reasons to let the economic optimism begin.” / The New York Times

Older people typically prefer activities that are more inherently pleasing than self-improving—hence, they’ve had (relatively speaking) a better pandemic. / The New York Times

For your lockdown envy: attractive home studios owned by artists and architects. / The Modern House

Unrelated: Tinder plans to introduce in-app background checks. / BBC News

From photographer Chris Maggio: scenes from the last day on Earth. / Chris Maggio Photo Studio

"Preparing the runway for flights is a two-week process." How to operate an airport in Antarctica. / flightradar24