Subtrac--amend t trace time from quarantine period
@@ -21,10 +21,10 @@ Version 1.5.2 (2020-08-18)
- Modify ``cv.People.quarantine()`` to allow it schedule future quarantines, and allow quarantines of varying duration.
- Update the quarantine pipeline so that ``date_known_contact`` is not removed when someone goes into quarantine.
- Fixed bug where people identified as known contacts while on quarantine would be re-quarantined at the end of their quarantine for the entire quarantine duration. Now if a quarantine is requested while someone is already on quarantine, their existing quarantine will be correctly extended where required. For example, if someone is quarantined for 14 days on day 0 so they are scheduled to leave quarantine on day 14, and they are then subsequently identified as a known contact of a separate person on day 6 requiring 14 days quarantine, in previous versions of Covasim they would be released from quarantine on day 15, and then immediately quarantined on day 16 until day 30. With this update, their original quarantine would now be extended, so they would be released from quarantine on day 20.
-- Quarantine duration is now based on time since last contact with the confirmed case, not time since notification, which better aligns with real-world policies. This results in an overall decrease in time spent in quarantine when the ``trace_time`` is greater than 0. A known limitation is that contacts are identified on the day that the person being traced is diagnosed, rather than the actual date of contact, which could be several days before diagnosis. In reality, these days would be deducted from the quarantine period as well, so Covasim 1.5.2 does still overestimate quarantine duration, albeit less than previous versions. However, since the primary impact of quarantine is to limit transmission shortly after exposure, the dominant effect is how quickly contacts are placed onto quarantine, with the quarantine duration likely to have an important but secondary effect, so this is not expected to be a critical issue.
+- Quarantine duration via ``cv.People.trace()`` is now based on time since tracing, not time since notification, as people are typically instructed to isolate for a period after their last contact with the confirmed case, whenever that was. This results in an overall decrease in time spent in quarantine when the ``trace_time`` is greater than 0.
- *Regression information*:
- Scripts that called ``cv.People.quarantine()`` directly would have also had to manually update ``sim.results['new_quarantined']``. This is no longer required, and those commands should now be removed as they will otherwise be double counted
- - Results are expected to differ slightly because the handling of quarantines being extended has been improved, and because quarantine duration is now based on time since contact.
+ - Results are expected to differ slightly because the handling of quarantines being extended has been improved, and because quarantine duration is now reduced when by the ``trace_time``.
Version 1.5.1 (2020-08-17)
