Thread by @rvenkayya

THREAD

Some say life will only get better at a "herd immunity" threshold, others say we only need to vaccinate high-risk people.

Bottom line: every additional person vaccinated helps everyone in the community, *including those already vaccinated.* 🧵 1/

https://twitter.com/rvenkayya/status/1367544912217075716?s=20

Direct protection from vaccines (protection of the vaccinated person) goes a long way toward limiting illness and death, but indirect protection massively amplifies the impact. Here’s a good explainer from @ZoeMcLaren. 2/

https://twitter.com/ZoeMcLaren/status/1373722257957195777?s=20

We need to maximize *indirect* protection to:
🔹Protect *vaccinated* persons who are still susceptible to disease
🔹Protect those who haven’t been vaccinated, including children
🔹Prevent Long COVID
🔹Protect everyone against variants.

Let's look at each. 3/

Many *vaccinated* persons will benefit from indirect protection, including:
🔹Immunocompromised persons who have an inadequate vaccine response
🔹Persons who may develop COVID-19 despite vaccination, as protection ≠ 100%
🔹Vaccinated persons whose immunity wanes pre-booster. 4/

Unvaccinated persons *depend* on indirect protection, including:
🔹Children, who can develop severe disease in rare instances
🔹Those who don't yet have access to vaccines, which is most of the world's population until 2022+. 5/

@collinskeith @Josh_H

nytimes.com/interactive/20…

Why else does this matter? Long COVID.

Vaccines should protect against Long COVID, but indirect protection can eliminate the risk entirely by preventing exposure in the first place. 6/

@KatherineJWu

theatlantic.com/health/archive…

But the most important reason may be the threat of variants, which could make all of the above worse.

Significant population immunity against “classic” SARS-CoV-2 should make it harder for new variants to spread, even those with immune escape potential. 7/

The bottom line is that every single person vaccinated in a community helps everyone else (and indirectly the rest of the world), whether they have been vaccinated or not.

We need to maximize uptake of vaccines *everywhere*, and do that as fast as possible. 8/