How long before I show signs and symptoms?
Available evidence supports that half of those infected will display symptoms of the illness five days following exposure, with 97.5% developing signs and symptoms of the illness within 12 days of exposure to COVID-19.
Data culled from 181 individuals who tested positive for COVID-19, whose exposure to an individual with COVID-19 had been confirmed and whose onset of symptoms was documented, provided the evidence for these conclusions about incubation. Although some developed symptoms between 12-14 days following exposure, only 2.5% of the test group (approximately four individuals) fell within this parameter. Results of this study can be found here.
Clinical signs and symptoms of mild-to-moderate COVID-19 can be found here. If you have symptoms that are more significant than those reported here, seek treatment from your physician.
How long am I contagious?
Little data is available that provides an adequate answer to this question as there is insufficient data to understand for how long COVID-19 makes a person contagious. However, looking to the timeline of other viruses does add some perspective to this question.
Clarifying terminology is initially important. When discussing the period during which a disease can be transmitted from one person to another, the terms “contagious” or “infectious” are routinely used. “Viral shedding” is another term used by scientists and medical professionals to define this period of contagion. During a viral shedding period, the viral host can actively shed the disease to others when the illness is present in the host.
A study performed in Nicaragua to determine the transmission of influenza in children and adults can be used to understand the length of time a person is infectious or can “shed” the virus. Between 2012 and 2014, the period over which four influenza variants had been detected in hosts, 144 cases and 112 household contacts were enrolled in the study. Over a period of 10-14 days after testing positive via the QuickVue Influenza A+B rapid test (a qualitative nasal/oral swab test), five home visits were conducted during which additional respiratory samples were collected from the infected individuals, and those in the same household with the infected individual.
Results of this study revealed the following:
Why should this influenza investigation be used as a guide to understand COVID-19?
What does this influenza study reveal about COVID-19?
Although we still do not know how long viral shedding occurs before a person displays symptoms of COVID-19, or for how long he or she is infectious after symptoms are detected, the fact that a person can be contagious for this period explains the need for social distancing, hand washing and other sanitary measures.