This is an email from Your Coronavirus Update, a newsletter by Medium Coronavirus Blog.

The Latest: Trump tests positive. Here are the facts.

Dear Reader,

What a day. President Donald Trump has tested positive for Covid-19, as well as first lady Melania Trump, Trump’s advisor Hope Hicks, and others. By now, you probably know this. We figured that would be the case, so we delayed this newsletter a bit today so we could spend more time with the news, the experts, and the facts.

There’s a lot of questions about what this might mean, and we have answers for you.

READ: Donald Trump Tests Positive for Covid-19. Here’s What We Know.

If there’s one clear takeaway for the American people it’s that masking and distancing are so important. You cannot rely on tests alone. The White House had a very regular testing protocol (the President was tested daily). But not wearing masks, not distancing, and spending significant time indoors without those precautions means that even the most theoretically protected people can still contract Covid-19 and spread it widely. To prevent Covid-19, you should embrace the science-backed measures recommended by experts.

Follow our Medium Coronavirus Blog for regular updates, and read some of the essential stories we’ve curated below.

Be well,

Alexandra Sifferlin
Editor, Medium Coronavirus Blog

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It’s time to use our Covid-19 knowledge to understand exactly what this means, and answer some burning questions.

Is everyone at the debate going to get sick? Not necessarily, but it’s time to be vigilant. Though there was distancing at the debate, the event was still held indoors, which makes viral transmission easier. Not everyone was wearing masks. It’s unclear if Trump and his team were infectious on Tuesday. People tend to be most contagious a few days before they develop symptoms. (Read this to understand more about viral load)

Biden tested negative. He’s in the clear, right? The negative test is good news but he’s still within the incubation period of the virus. The incubation period is two to 14 days but is typically closer to 4–5 days. It’s highly likely that Biden will get tested a second time (also to confirm it’s not a false negative). More on false negatives and positives here in a helpful Covid-19 glossary.

What happens now? Contact tracing! Any close contacts of the President need to get tested and should begin a strict 14-day quarantine since the day of their exposure to Trump or anyone else in the cluster who has tested positive. Even if the initial tests are negative, the contacts need to do regular testing to pick up cases as fast as possible. (Here’s a quick 101 on contact tracing the President)

An important thing to keep in mind is that it’s unknown who the initial case is. It’s possible that the same person infected both the President and Hope Hicks. Isolating potential cases is what will help stop the chain of transmission.

The lessons we can learn from Trump’s diagnosis. As my colleague Anna Maltby writes, Trump testing positive has “sparked questions, speculation, and countless Twitter hot takes” and there’s plenty of lessons including, frequent testing is not a silver bullet, even people you trust can get sick, and symptoms should be taken seriously as soon as they appear. Read more here.

This is why you mask-up. “This is the perfect demonstration of the fact that there is no one silver bullet [for preventing Covid-19],” Nahid Bhadelia, MD, MA, medical director of the Special Pathogens Unit at Boston Medical Center tells the Blog. “What always seemed obvious is that the administration’s strategy has been so heavily dependent and reliant on this testing…No test is infallible.” Read more.

Keep calm and stay alert. There’s already plenty of conspiracies spreading about Trump’s Covid-19 diagnosis, even though there are not many more details about his condition at this moment. “That’s why it’s important, now, to be extra-vigilant about misinformation, which has flooded the internet in light of the president’s tweet,” my colleague Yasmin Tayag writes on the Blog. Read more about how to cut through the noise.

Share this with the non-expert in your life who won’t stop talking about vitamin D. There’s been so much hype about the potential link between vitamin D supplementation and Covid-19 protection. Epidemiologist Gideon Meyerowitz Katz writes a thorough review of the recent studies and shares everything you need to know about what the science really says, and how you should interpret it for your own life. Read on for advice.

You cannot hang out indoors! It sucks, we know. But unless you are in a carefully orchestrated bubble or pod, it’s simply not a good idea right now. The fall surge has begun and cases are picking up. Plus, Covid-19 spreads much easier inside than outside. If you are invited to an indoor, maskless Halloween party you should absolutely cancel. Read the full story here.

5 Ways to Deal With WTF is Going On Right Now

Study Finds US President Greatest Source of Fake News About Covid-19

The Bold Attempt to Grow a Covid-19 Vaccine in Plants

Why Losing Your Sense of Smell With Covid-19 Is So Traumatizing

The Impact of Police Brutality on Covid-19 and Medical Mistrust

This Overlooked Variable Is the Key to the Pandemic (The Atlantic)

Alexa, Do I Have Covid-19? (Nature)

“Covid brought all of my deepest fears, anxieties, and vulnerabilities to the surface — about my health, my heartiness, my luck, my future.”

— Liz Kotin, Battling Covid-19 Showed Me the Limits of My Mind

Health and science journalist. Former editor of Medium’s Covid-19 Blog and deputy editor at Elemental. TIME Magazine writer before that