We are still learning what are the true symptoms of COVID-19. We are starting to learn that this virus is mutating and evolving, and people in different parts of the world have different symptoms. In this post, I will summarize the reports of the symptoms of COVID-19 from China.
On average, the incubation period is 5.2 days, meaning that people are asymptomatic for that length of time before they start to notice the first symptom. (Li et al. NEJM 2020) https://www.nejm.org/doi/10.1056/NEJMoa2001316.
The most common symptoms someone first experiences are fever, cough, and fatigue. Other symptoms people experience include sputum production, headache, bloody vomit, diarrhea, and shortness of breath. (Rothan et al. Autoimmunity 2020 ) https://www.sciencedirect.com/science/article/pii/S0896841120300469#bib8
Source: Rothan et al. 2020
Below is a table of the most common symptoms for those hospitalized from COVID-19. https://jamanetwork.com/journals/jama/fullarticle/2761044
Source: Wang et al. JAMA 2020.
Looking at these numbers, it appears that a criteria for admission to the Chinese hospitals during the initial COVID-19 outbreak is fever. This is probably the driving cause for the current CDC guidelines, described below.
However, looking at the literature, there scariest statistic is that after people first develop these first concerning symptoms, it can rapidly progress to acute respiratory distress syndrome and admission to an intensive care unit.
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30183-5/fulltext
https://jamanetwork.com/journals/jama/fullarticle/2761044
Source: Huang et al. Lancet 2020.
The complications within the hospital for COVID-19 are severe. We know that the virus requires ACE2 receptors, which are present in the lung, heart, and kidney, and the complications affect those vital organs.
Source: Wang et al. JAMA 2020.
The major takeaway from this summary is that we need to take this disease extremely seriously. People are asymptomatic for a while, but once they develop a concerning symptom like fever or shortness of breath, they can rapidly decline after a couple days.
