This Singapore study seems relevant
1/ to the current UK isolation advice &
2/ the fact surrounding the Cummings’ saga remembering the known timelines of activity for all 3 members of the family.
Conclusions
A/ Infectious whilst asymptomatic? Yes
ams.edu.sg/view-pdf.aspx?…
1/ to the current UK isolation advice &
2/ the fact surrounding the Cummings’ saga remembering the known timelines of activity for all 3 members of the family.
Conclusions
A/ Infectious whilst asymptomatic? Yes
ams.edu.sg/view-pdf.aspx?…
B/ The infectious period of SARS-CoV-2 in symptomatic individuals may begin around 2 days before the onset of symptoms, and persists for about 7 - 10 days after the onset of symptoms.
No evidence that infectiousness sustained 2 weeks after developing symptoms.
No evidence that infectiousness sustained 2 weeks after developing symptoms.
C/ The practice of RT-PCR testing for negative results in fact is inconclusive because, as with other studies, people were found to be shedding virus for 28 days, some even longer, but no shedded virus 14 days after symptom onset was found to be viable despite RT-PCR positives.
These data corroborate the epidemiologic data and indicate that while viral RNA detection may persist in some patients, such persistent RNA detection represent non-viable virus and such patients are non-infectious.
D/. It was a Hong Kong study that suggested that asymptomatic transmission in that paired groups indicated that the duration between symptom onset of a primary case to symptom onset of its secondary case) of COVID-19 was 5.8 days (mean)...
.. with 7.6% of serial intervals distributed negatively (i.e. the infectee developed symptoms prior to infector) strongly implying pre-symptomatic transmission.
Assuming a median incubation period of 5.2 days (based on other studies), the study estimated that the infectious period of SARS-CoV-2 started 2.3 days before onset of symptoms, peaking at 7 days, and declining within 7 days.
So there is an infectiousness curve with evidence it can start more than two days before symptoms, persisting markedly for 7 days after getting symptoms and existing but diminishing over the subsequent 7 days.
