Exposure Quarantine Window

Apply a caller-defined incubation-quantile and buffer rule to the latest exposure day; policy values are not embedded.

Description

Calculate the end and remaining duration of a caller-defined window from last exposure, an incubation-duration quantile, and a buffer.

An incubation distribution describes variation in the time from infection to symptom onset. A chosen quantile is a duration by which a specified proportion of incubation times falls under that distribution; it does not imply that every infection has become symptomatic.^[1]

This calculator adds a supplied duration and buffer to a last-exposure day. Its policyEndDay label refers to the endpoint of that arithmetic window, not to a policy retrieved or selected by the tool. Fractional days are valid if every input uses the same time axis.

Exposure Quarantine Window returns the endpoint, nonnegative remaining days, and whether the supplied window has elapsed. It does not determine whether a person is infected, infectious, or eligible for release.

When to check a supplied exposure-based time window

Use the tool after selecting the applicable window parameters outside the calculator. It can check schedule arithmetic or compare hypothetical duration assumptions while retaining their source and scope.

Add a supplied incubation-duration quantile and buffer to an exposure day.
Check elapsed status at an evaluation day.
Keep remaining time from becoming negative after the endpoint.

How to enter duration parameters and calculate the endpoint

Enter nonnegative Last exposure day and Evaluation day on the same day axis.
Enter nonnegative Incubation quantile days as a duration in days, not a probability such as 0.95.
Enter nonnegative Buffer days chosen for the analysis.
Run the calculation and read Policy end day, Remaining days, and Policy window elapsed.

policyEndDay = lastExposureDay + incubationQuantileDays + bufferDays; remainingDays = max(0, policyEndDay − evaluationDay)

The boolean uses evaluationDay ≥ policyEndDay. Equality means elapsed, and remaining duration stays zero after the endpoint.

json

{
  "input": {
    "lastExposureDay": 3,
    "incubationQuantileDays": 10,
    "bufferDays": 2,
    "evaluationDay": 14
  },
  "output": {
    "policyEndDay": 15,
    "remainingDays": 1,
    "policyWindowElapsed": false
  }
}

Zero durations and a zero buffer are allowed. The tool does not require evaluation day to follow last exposure; an earlier evaluation still returns the arithmetic time to the endpoint. Negative inputs, malformed fields, and nonfinite values produce errors.

Limitations and interpretation

No jurisdiction, current public-health guidance, symptom history, testing rule, or exposure classification is consulted.
The selected duration and buffer are caller assumptions; their appropriateness is not assessed.
Window elapsed states only that the supplied endpoint has been reached, not that transmission risk is zero.
Continued or repeated exposures require an updated last-exposure input; they are not detected automatically.

Alternative or Complementary methods

Exposure-window bounds summarize uncertain infection timing rather than selecting a quarantine duration. A test-based isolation screen applies a separately supplied sequence rule and remains a different calculation.

References

The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application — Annals of Internal Medicine; S. A. Lauer and colleagues (2020)

Similar or alternative tools

Incubation Exposure Bounds
Calculate possible incubation-duration bounds from exposure windows and onset times.
Test Based Isolation Release
Evaluate a caller-defined consecutive-negative test criterion and earliest eligible day.