The natural history COVID-19
What can happen after infection?
by Jamal Ross
After an initial incubation period, most of those infected with the coronavirus will have mild symptoms. Yet there is a considerate number of individuals that will develop severe symptoms and critical disease. Let’s take a look at the different paths of illness one can take after being infected with the coronavirus.
After being exposed to someone with the coronavirus, there is a certain amount of time that is needed for the virus to replicate and begin to cause symptoms. This is called the incubation period. The incubation period for the COVID-19 virus can last up to 14 days. (1) During this time, an individual may have no symptoms, but will continue to be infectious. Once symptoms begin, one may complain of fever, muscle aches, headaches or cough. These symptoms are similar to those cause by other viruses and are therefore called non-specific symptoms. Of those infected with COVID-19, 81% will have mild symptoms and recover without requiring oxygen or hospitalization. (2) Even those wild mild symptoms may have a prolonged course and not feel at their baseline until after 3 weeks (3)
Other the other hand, 14% of those infected with the coronavirus will have severe symptoms. (2) These symptoms included shortness of breath and the need for oxygen. Interestingly, about 1 week after experiencing mild symptoms, this group will begin to have shortness of breath and a chest x-ray that shows pneumonia. Symptoms can continue to progress to include the need to be hospitalized and placed on a ventilator. While some may recover after a long hospital stay, others with underlying medical conditions can pass away.
Finally, 5% of those infected with COVID-19 will have critical disease. (2) After the incubation period and mild symptoms, individuals in this group can quickly develop respiratory failure and require a ventilator. Also, those in this group can have cardiac complications including shock and heart arrhythmias. Blood clots in the lungs and strokes due to blood clots in the brain can also be seen.
In all, although the majority of individuals with COVID-19 will have mild symptoms and recovery without long term complications, this virus remains dangerous and deadly for a significant percentage of the population. Once COVID-19 has caused pneumonia, there can be a cascade of events leading to the need for a ventilator as well as life changing heart complications and stroke. Prevention remains the most effective methods to combat this virus. It is difficult to fight the coronavirus in a hospital bed while on a ventilator. Even if you survive, the recovery may be prolonged and difficult. Therefore, if you have COVID-19 and you began to have worsening shortness of breath, it is important to seek medical attention. Even if your symptoms are mild, it is essential that you do not pass this virus onto others.
1. Guan WJ, Ni ZY, Hu Y, Liang WH, Ou CQ, He JX, Liu L, Shan H, Lei CL, Hui DSC, Du B, Li LJ, Zeng G, Yuen KY, Chen RC, Tang CL, Wang T, Chen PY, Xiang J, Li SY, Wang JL, Liang ZJ, Peng YX, Wei L, Liu Y, Hu YH, Peng P, Wang JM, Liu JY, Chen Z, Li G, Zheng ZJ, Qiu SQ, Luo J, Ye CJ, Zhu SY, Zhong NS; China Medical Treatment Expert Group for Covid-19. Clinical Characteristics of Coronavirus Disease 2019 in China. N Engl J Med. 2020 Apr 30;382(18):1708-1720. doi: 10.1056/NEJMoa2002032. Epub 2020 Feb 28. PMID: 32109013; PMCID: PMC7092819.
2. Wu Z, McGoogan JM. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China: Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention. JAMA. 2020 Apr 7;323(13):1239-1242. doi: 10.1001/jama.2020.2648. PMID: 32091533.
3. Tenforde MW, Kim SS, Lindsell CJ, Billig Rose E, Shapiro NI, Files DC, Gibbs KW, Erickson HL, Steingrub JS, Smithline HA, Gong MN, Aboodi MS, Exline MC, Henning DJ, Wilson JG, Khan A, Qadir N, Brown SM, Peltan ID, Rice TW, Hager DN, Ginde AA, Stubblefield WB, Patel MM, Self WH, Feldstein LR; IVY Network Investigators; CDC COVID-19 Response Team; IVY Network Investigators. Symptom Duration and Risk Factors for Delayed Return to Usual Health Among Outpatients with COVID-19 in a Multistate Health Care Systems Network – United States, March-June 2020. MMWR Morb Mortal Wkly Rep. 2020 Jul 31;69(30):993-998. doi: 10.15585/mmwr.mm6930e1. PMID: 32730238; PMCID: PMC7392393.