Thread by @Anna_Rothschild

In interviews with scientists over the past few weeks, @sindujas and I have heard multiple times that we are probably not going to reach herd immunity with COVID-19 (at least not in a sustainable way). But that doesn’t mean we’re doomed. A 🧵 fivethirtyeight.com/features/turni…

Throughout the pandemic there’s been a ton of talk about herd immunity. For many people, I think they assume that once we reach herd immunity the virus will just disappear.

Maybe it would be like measles, a disease we haven’t totally eradicated, but we’ve largely eliminated from most parts of the US through widespread vaccination.

The thing is, when you get the measles vaccine, that immunity can last for life.

We have more and more evidence that the COVID vaccines not only block symptoms but also block transmission to some extent. BUT we don’t know how long that immunity lasts. Heck, we don’t even know how long immunity from getting COVID lasts!

And we do know that we can get other coronaviruses multiple times…

Without that long lasting immunity, it’s unlikely that we’d be able to maintain herd immunity.

Also some clarification: herd immunity is a very specific thing. It doesn’t just mean you’ve lessened transmission. It means so many people are immune that it’s basically impossible for there to be an outbreak in the population.

Many scientists now think COVID will become endemic, meaning that it’s always floating around in the population. Other endemic diseases? Flu, the common cold, etc…

The sounds scary, but fear not! First, through vaccination, we can minimize the risks associated with getting COVID.

The three vaccines in the US have different efficacy rates (95% for Pfizer & Moderna and 72% for Johnson and Johnson). But in trials ALL THREE PREVENTED 100% OF HOSPITALIZATIONS AND DEATHS.

Sorry to scream, but I think that’s really important. COVID is scary because it kills people. Our vaccines do a really good job of keeping people alive and out of the hospital.

So one idea is that the virus becomes endemic, and we vaccinate ourselves out of the danger zone. It gets spread around every year like the flu, but we don’t see nearly the number of deaths.

But there is another, super cool hypothesis about how COVID might become just another common cold. (Well…it’s super cool if you’re a science nerd like me.)

A number of COVID’s cousins cause the common cold. Basically every person on the planet gets these viruses in early childhood. But…what would happen if you got them for the first time as an adult?

We don’t know. But scientist Jennie Lavine from @EmoryUniversity thinks it’s possible that if we all got exposed to COVID as a baby/young kid, the virus could become just another common cold.

And at some point in the not-so-distant future, the only people who will be exposed to COVID for the FIRST time will be babies/young kids, because all adults will have been vaccinated or gotten COVID.

This might seem sort of crazy, but there is a really fascinating story (about a COVID cousin) that makes a compelling case for this hypothesis.

One common cold coronavirus is called OC43. Through genetic studies, scientists know it emerged in the late 1800s in Europe.

What else was happening in Europe at the time? A really awful disease that people, called "The Russian Flu" (cause it was first found in Russia) that killed a lot of people.

Could the Russian Flu have been OC43 before it became endemic? We're obviously not sure...but it's a VERY exciting idea. (Again, if you are a science nerd.)

Anyway, TL;DR there are multiple ways out of this pandemic, but they all rely on vaccination. Whether or not the virus becomes endemic, we’re going to need to get a bunch of people immunized.

And remember, vaccinations do more than prevent illness. They also give the virus fewer opportunities to spread and replicate, which means there are fewer changes for the virus to mutate.

Waaaaay more on all of this (and a whole section on navigating risk when you are/aren't vaccinated) in the most recent episode of Podcast-19 from @fivethirtyeight. Let me know if you have any questions!