14 days quarantine and contact tracing can be ineffective to contain the virus
In a newly released pre-print individually documented case descriptions of COVID-19 from China was used to estimate the distributions of the generation time, incubation period, and periods from symptom onset to isolation and to diagnosis. Resarchers found that 14-day quarantine period may lead to a 6.7% failure rate for quarantine. Instead they recommend a 22-day quarantine period. The mean incubation period was found to be 7.2 days and it took on average 3.7 days to isolate and 6.6 days to diagnose a patient after his/her symptom onset.
Furthermore the researchers found that patients may become infectious on average 3.9 days before showing major symptoms, and the conclusion is that contact tracing and quarantine are ineffective. The basic reproduction number, R0, is estimated to be 1.54 with contact tracing, quarantine and isolation, and it is appears that this number is mainly due to so-called super spreaders.
I would hope that governments and authorities take research in consideration and review their battle plans on how to fight COVID-19. A 6.7% failure rate of quarantine may sound negligeble, but every percent counts. In principle, strict hygiene measures, a three week (volontary) isolation for everyone with flu-like symptoms might be a good start.