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

The Latest: New Rules for Air Travel ✈️

Dear Reader,

As winter storms pummeled the United States this week, it was hard not to daydream of traveling to sunnier climes. Doing so is not recommended, of course (I’m looking at you, Ted Cruz), and with good reason: Though the winter surge in new cases is finally relenting, more transmissible — and possibly more lethal — variants are afoot.

The CDC recently updated its recommendations for international air travel to reflect this new reality. Now, anyone flying into the United States must get tested no more than three days before traveling and show proof of a negative result before boarding. Even this might not be enough to contain the spread, though. Harvard epidemiologist Michael Mina, MD, recently said pre-flight testing three days before traveling was “not effective, period.” A negative test result three days before your trip does not guarantee you won’t be contagious when you travel.

Mina is calling on the Biden administration to invest in rapid testing so people can find out whether they’re contagious in real time. This would not only help open up air travel, but also schools, sports games, and virtually any other public venue.

Until that happens — and Mina suggests there’s good reason to believe that it will — it’s best for everyone to avoid travel as much as possible, no matter how cold it gets outside.

As always, feel free to send me any questions or comments via email. I’d love to hear from you!

Stay safe and stay hopeful,

Yasmin Tayag
Editor, Medium Coronavirus Blog

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While wealthy countries like the United States and the U.K. have acquired enough of the vaccine for their entire populations, many nations have not even received their first shipment of doses. And as emergency room physician Craig Spencer, MD, MPH wrote in Elemental this week, ensuring vaccination is equitable around the world should be a public health concern for everyone. That’s because variants will continue to develop as long as the virus continues to infect people. And as we’re seeing now, these variants can travel all over the world, no matter where they first originate. Read more.

NBA data reveals new info about the B.1.1.7 variant. We’re big basketball fans here at the Blog, and it’s been awesome to see the NBA play such an important role in Covid-19 research. The league has diligently tested and tracked its players and staff, resulting in a huge amount of data that scientists can use to study the coronavirus. As my colleague Dana Smith wrote in the Coronavirus Blog this week, Harvard researchers recently used the NBA’s data to learn something new — and rather alarming — about the B.1.1.7 variant, which was first identified in the U.K. The data suggest that people infected with the variant have longer infections, which may explain why it is more transmissible. Read more.

All Americans can get vaccinated by late July. In a CNN Town Hall this week, President Joe Biden said that vaccines will be available to the general public by the end of July. At that point, he said, the U.S. will have 600 million doses — enough for all Americans to get vaccinated. His administration also increased the weekly allotment of doses for each state to 13.5 million doses per week, which should go a long way in speeding up vaccination efforts across the country. Read more.

People who have had Covid-19 may only need one dose. Preliminary research is increasingly suggesting that people who have had Covid-19 may only need one dose of a two-dose vaccine, rather than the full regimen. As Elad Simchayoff wrote on the Coronavirus Blog this week, studies suggest that a dose administered to someone who has recently been infected with Covid-19 can act as a “booster” shot, provoking the production of more antibodies. Read more.

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