Started Jun 18, 2021 05:00PM UTC   •   Closed Jul 18, 2021 06:00PM UTC

Tim Harford asks:

When will the Delta variant (B.1.617.2) first represent more than 67.0% of COVID cases in the US?

Delta variant (B.1.617.2, formerly known as the India variant) case growth in the United States raises concerns about a possible worsening of the COVID-19 pandemic in the fall (CBS News, CNN). The CDC estimates proportions of SARS-CoV-2 lineages circulating in the United States, grouped in 2-week intervals, here: https://covid.cdc.gov/covid-data-tracker/#variant-proportions. For the week ending 22 May 2021, the Delta variant's percent share of COVID lineage in the US was 2.7% as of the launch of this question. Data from the “Nowcast” option would count.

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The question closed "The two weeks ending either 17 July 2021 or 31 July 2021" with a closing date of 18 July 2021.

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Possible Answer Correct? Final Crowd Forecast
The two weeks ending 3 July 2021 or earlier 0%
The two weeks ending either 17 July 2021 or 31 July 2021 99%
The two weeks ending either 14 August 2021 or 28 August 2021 1%
The two weeks ending 11 September 2021 or 25 September 2021 0%
Not before 26 September 2021 0%

No. of
Forecasters

89

Forecast
Count

272

Crowd Brier Score

0.0162


Most Accurate

Relative Brier Score

1.
-0.079
2.
-0.078
3.
-0.078
4.
-0.076
5.
-0.076

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