Source page: McKinsey & Company
Commentary
US most likely to reach COVID-19 herd immunity in second half of 2021
COVID-19 | Public Health
September 30, 2020 – While the US is most likely to reach COVID-19 herd immunity in the third or fourth quarter of 2021, it could come as early as the second quarter of 2021, if vaccines are highly effective and launched smoothly, or if significant cross-immunity is discovered in a population. But if early vaccine candidates have efficacy or safety issues, the pandemic could extend until 2022 or later.
To read the article, see “When will the COVID-19 pandemic end?,” September 21, 2020.
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Visual form
Table (with Visual Encoding): quarter-by-quarter scenario timeline for US COVID-19 herd immunity.
Layout / body structure
The timeline reads left to right across quarters. Scenario windows are placed from the earliest plausible outcome through the most likely window and then into delayed outcomes on the right.
What is being compared
It compares alternative timing scenarios for US herd immunity under assumptions about vaccine effectiveness, rollout smoothness, cross-immunity, and vaccine safety or efficacy setbacks.
Measurement system
The measure is projected calendar timing by quarter and year. The visual encodes scenario likelihood and timing rather than case counts or death counts.
Visible structure inside the graphic
The central emphasis is on the second half of 2021, with an earlier edge in the second quarter of 2021 and later scenarios extending into 2022 or beyond.
Main takeaway from the visual
The chart shows that the most likely herd-immunity window was the third or fourth quarter of 2021, but that the date could move earlier or later depending on vaccine performance and rollout conditions.
Key standout values or extremes
The earliest plausible window is the second quarter of 2021. The most likely window is the third or fourth quarter of 2021, and the delayed edge reaches 2022 or later.
Controls / sequence, when applicable
This is a static visually encoded scenario timeline; there are no in-chart controls to operate.
Companion media, when applicable
There is no separate companion audio or video; the herd-immunity scenario timeline is the full visual on this page.