Thread by @yaneerbaryam

In the past month, US effective reproduction number (Rt) has risen from 0.78 (historical low), back up above R=1.

Why is Rt rising? We keep relaxing restrictions, and new variants are accelerating transmission even as vaccinations are happening

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This shows up in case counts, where the recent decline in cases has reversed and cases are now growing. With reopening across the country, as well as new variants, growth will accelerate into a “4th wave”

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Vaccinations shouldn't be expected to be a get-out-of-jail-free card in ending the pandemic. New variants not only accelerate transmission, they can undermine immunity of prior infection and vaccination. The best strategy is to aim for elimination using vaccination to help.

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Europe is a couple steps ahead in seeing the variants. The UK, for example, is applying tougher restrictions just to achieve the same level of R they've had previously.

Running faster and faster just to stay in one place.

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Once one grasps this pattern, it helps explain why #ZeroCovid #nocovid is gaining popularity in Europe. An opportunity to break the cycle of yo-yo lockdowns, new variants etc., with strong, early, decisive action. ("Early" relative to years of Covid we could still face)

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To quote @rdmorris, "Letting COVID-19 spread while we slowly roll out a vaccine, is like a person with a bacterial infection taking antibiotics at too low a dose." It won't kill the infection, and the bacteria that remain will be those with resistance to the drug.

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Europe's struggle with new variants are a preview of what's expected in the US, once B117 becomes dominant here as it has there. Everyone will have to work harder than ever to keep the pandemic from growing, let alone to have it decrease.

...and then there is the next one.

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[Thanks to @geekblake, @VanGennepD and @realsmartchange for helping prepare today's update!]