Thread by @sarahzhang

I wrote about how all the signs are pointing to herd immunity against COVID-19 becoming impossible.

This is how the pandemic ends instead—because yes, it can still end.

theatlantic.com/health/archive…

1/

For herd immunity, we need vaccines to prevent transmission. They probably will to some extent but we should expect that protection to

- be weaker than protection against symptomatic infection
- wane over time
- be eroded first by new variants

2/

The herd immunity threshold was always going to be a challenge & variants make it even harder.

That means COVID-19 will probably keep circulating but the good news! Vaccines can still prevent people from getting seriously sick & dying. Life is normal again. Pandemic ends. 3/

Frankly, preventing severe disease is all scientists expected of vaccines, as I wrote last year, before we knew the vaccines would be so good.

The 95% efficacy number got hopes up, and now the variants are tempering them again. 4/

theatlantic.com/health/archive…

At the start of the pandemic, COVID-19 had 3 possible fates:

1) global elimination like SARS
2) local elimination through herd immunity like measles
3) endemic like common cold coronaviruses

5/

#1 has been a foregone conclusion since at least last spring. #2 looked possible for a while. #3 was always the most likely and now seems even more so.

6/

Another analogy is influenza. When flu pandemics end, that virus doesn’t disappear. It becomes the dominant seasonal flu for years afterward.

We’re going to be living with this coronavirus for a long time, but vaccines will make it a lot easier to live with.

7/

Personally, the “no herd immunity” scenario makes me more eager to get vaccinated. It means I will probably get exposed COVID-19 at some point, and I’d much rather have some immunity from a vaccine than none at all.

/end