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| Period of Observation | Estimate (95% confidence interval) | |
|---|---|---|
| Non-healthcare worker | Healthcare worker | |
| April 16, 2020 to December 20, 20201 | 0.35 (0.31, 0.38) | 0.27 (0.23, 0.31) |
| April 16, 2020 to February 15, 20212 | 0.49 (0.47, 0.52) | 0.83 (0.82, 0.85) |
1. Probability of prior infection (before vaccines).
2. Probability of prior infection or vaccination.
