[Goose]

If you look at figure 2 in this paper, it provides the cumulative distribution function of the incubation period.

Based on the figure, the median incubation period is 7 days (table 2 estimates it at between 5 and 7 days).  Depending on the model, the 95th percentile (that is, 95% of the time, the incubation period is that length or shorter) is 10 - 13 days depending on which model is chosen.  The 99th percentile 12 to 18 days, again depending a bit on the model.

Here's a review paper that finds something similar.

Results The incubation period distribution may be modelled with a lognormal distribution with pooled mu and sigma parameters (95% CIs) of 1.63 (95% CI 1.51 to 1.75) and 0.50 (95% CI 0.46 to 0.55), respectively. The corresponding mean (95% CIs) was 5.8 (95% CI 5.0 to 6.7) days. It should be noted that uncertainty increases towards the tail of the distribution: the pooled parameter estimates (95% CIs) resulted in a median incubation period of 5.1 (95% CI 4.5 to 5.8) days, whereas the 95th percentile was 11.7 (95% CI 9.7 to 14.2) days.

So, reducing the quarantine period would increase the risk that someone on the tail end of the distribution makes it through.  However, assuming the more optimistic model is correct, you can probably reduce the quarantine period to 10 - 12 days and still be able to catch about 95% of secondary cases.  If you add asymptomatic testing at the end, you will probably catch some asymptomatic and pre-symptomatic secondary cases that may not have become symptomatic until the tail end of the distribution.

On that basis, I think a 10-day quarantine period with testing at the end probably is supported.  A seven day quarantine period is probably too short.

BC

Once again we have to thank BC for providing the information. I would point out that a reduction to 10 day quarantine relies on the more optimistic study results and also on the idea asymptomatic testing at the end would reduce the 10 day rate to 95%. I guess it also requires the minimum target goal to be 95%. We really don't have the data to say that this testing would accomplish that, so if it were me, I would say 12 days. YMMV. There are two important points to be made here, IMHO. First, 7 days clearly is too short. Second, whatever the CDC changes it's recommendations to be (if indeed it does so), it needs to provide an equivalent analysis to what BC has provided here. If they do not, I will be very disappointed and very suspicious. It can be done, we see it here. Not doing so would be malfeasance on the part of the CDC.

[Goose]

If you look at figure 2 in this paper, it provides the cumulative distribution function of the incubation period.

Based on the figure, the median incubation period is 7 days (table 2 estimates it at between 5 and 7 days).  Depending on the model, the 95th percentile (that is, 95% of the time, the incubation period is that length or shorter) is 10 - 13 days depending on which model is chosen.  The 99th percentile 12 to 18 days, again depending a bit on the model.

Here's a review paper that finds something similar.

Results The incubation period distribution may be modelled with a lognormal distribution with pooled mu and sigma parameters (95% CIs) of 1.63 (95% CI 1.51 to 1.75) and 0.50 (95% CI 0.46 to 0.55), respectively. The corresponding mean (95% CIs) was 5.8 (95% CI 5.0 to 6.7) days. It should be noted that uncertainty increases towards the tail of the distribution: the pooled parameter estimates (95% CIs) resulted in a median incubation period of 5.1 (95% CI 4.5 to 5.8) days, whereas the 95th percentile was 11.7 (95% CI 9.7 to 14.2) days.

So, reducing the quarantine period would increase the risk that someone on the tail end of the distribution makes it through.  However, assuming the more optimistic model is correct, you can probably reduce the quarantine period to 10 - 12 days and still be able to catch about 95% of secondary cases.  If you add asymptomatic testing at the end, you will probably catch some asymptomatic and pre-symptomatic secondary cases that may not have become symptomatic until the tail end of the distribution.

On that basis, I think a 10-day quarantine period with testing at the end probably is supported.  A seven day quarantine period is probably too short.

BC

Once again we have to thank BC for providing the information. I would point out that a reduction to 10 day quarantine relies on the more optimistic study results and also on the idea asymptomatic testing at the end would reduce the 10 day rate to 95%. I guess it also requires the minimum target goal to be 95%. We really don't have the data to say that this testing would accomplish that, so if it were me, I would say 12 days. YMMV. There are two important points to be made here, IMHO. First, 7 days clearly is too short. Second, whatever the CDC changes it's recommendations to be (if indeed it does so), it needs to provide an equivalent analysis to what BC has provided here. If they do not, I will be very disappointed and very suspicious. It can be done, we see it here. Not doing so would be malfeasance on the part of the CDC.