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

The Latest: New mask guidance

Dear Reader,

One of the most common questions I get from friends and family is: What kind of mask should I be wearing? I can’t blame them for wondering. The official guidance has changed multiple times as experts’ understanding of Covid-19 has improved. This week, as the new and more transmissible variants spread across the United States, it changed again.

The Centers for Disease Control and Prevention urged people to ensure their masks fit snugly on their face — mind the nose gap! — and use a mask with multiple layers, or double up. Similarly, Harvard professor and Biden Covid-19 advisor Atul Gawande, MD, recommended this week that people opt for disposable medical masks because cloth masks don’t fit well over the nose.

Though the guidance on masking has shifted, the basic concept behind it has not: Keep your respiratory droplets contained so that other people can’t breathe them in, just in case those droplets may carry Covid-19. As we work together to control the variants, careful mask wearing has never been more critical.

Stay safe and stay hopeful,

Yasmin
Editor, Medium Coronavirus Blog

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This week, World Health Organization scientists announced that it was “extremely unlikely” that the coronavirus was released in a lab accident. This “lab leak” theory gained credence in part because it was perpetuated, last year, by Donald Trump. Many scientists have already asserted that the virus had a natural origin, which the WHO experts, with 12 days’ worth of field research in hand, agreed with. However, it’s not yet known whether the virus jumped directly from animal to human or passed through an intermediate host. Read more about the ongoing investigation.

Biden secures enough doses for all Americans. Making good on a plan he announced at the end of January, President Biden revealed on Thursday that he had finalized a deal to get 200 million more vaccine doses from Pfizer and Moderna — 100 million from each company. This means the U.S. has now secured enough doses to vaccinate all Americans. Also on Thursday, infectious diseases chief Anthony Fauci, MD, said that most of the general public could start getting vaccinated by April, as more doses became available. He called it “open season.” Read more on this week’s vaccine updates.

Good news about quarantining for vaccinated people. The CDC’s latest guidance on quarantining held exciting news for people who have been fully vaccinated: If they come into contact with a person with Covid-19, they don’t have to quarantine for 14 days. Emergency room doctor Megan Ranney, MD, noted on Twitter that this decision is supported by early evidence showing that people who are fully vaccinated may get infected, but if they do, they have much lower titers of the virus. That means they’re less likely to transmit it. Read more about the new guidance.

Ongoing inequalities in the vaccine rollout. Earlier this week, 60 Black health experts wrote an op-ed in the New York Times urging Black Americans to get vaccinated. Their aim was to dispel misinformation about the safety of the vaccines spreading in Black communities. While this is a real issue, wrote Michael Arceneaux in Level this week, the more pressing concern is the fact that Black people who want to get vaccinated can’t access the vaccine. Adding to the inequality, people with asthma — a condition that affects Black and Brown people at disproportionately higher rates — are being excluded from priority vaccination, as Dana Smith wrote this week in Momentum. Read more.

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Editor, Medium Coronavirus Blog. Senior editor at Future Human by OneZero. Previously: science at Inverse, genetics at NYU.