People are very clueless about COVID-19 symptoms.
The symptoms may appear 2-14 days or more after exposure to the virus. Some infected people may have fever/chills, cough, shortness of breathing, fatigue, body aches, headache, loss of taste, sore throat, runny nose, nausea, vomiting or diarrhea and some people with underlying medical conditions may have higher risk for developing more complications. However, it was reported that many people infected with COVID-19 (Positive for COVID-19) have no symptoms at all!1
Do our genes predispose us to COVID-19?
Our genetic makeup could have been linked to variable clinical manifestations of COVID-19. In the past, the variations in the human genome has been shown to be related to the severity and susceptibility to various infections. In a genetic study, it was demonstrated that genetic variants of IL28B and HLA are associated with Hepatitis C virus (HCV) spontaneous resolution or clearance. It explains why some people with hepatitis C resolve spontaneously while others are left with chronic diseases.2 In addition, susceptibility to Human Immunodeficiency Virus (HIV) has been shown to be related to CCR5 gene which confers protection to the human host.3
Theoretically, these might explain why some people with positive COVID-19 have no symptoms at all and some are more prone life-threatening complication and eventually died. Is there any possibility that human genes have protective effects against the COVID-19 infection? This is yet to be confirmed.
Genetically, some people have protective genes that confer resistance towards infections while others are vulnerable to severe illness.4 Ongoing COVID Human Genetic Effect (https://www.covidhge.com/) and The COVID-19 Host Genetics Initiative (https://www.covid19hg.org/) are two of such initiatives aiming to uncover the genetic determinants of COVID-19 susceptibility, severity and outcomes.
- Asymptomatic coronavirus: how common is it and can its spread be contained? (May, 2020). Retrieved from https://www.theguardian.com/world/2020/may/30/covid-19-asymptomatic-coronavirus-how-common-is-it-and-can-its-spread-be-contained
- Duggal, P., Thio, C. L., Wojcik, G. L., Goedert, J. J., Mangia, A., Latanich, R., Kim, A. Y., Lauer, G. M., Chung, R. T., Peters, M. G., Kirk, G. D., Mehta, S. H., Cox, A. L., Khakoo, S. I., Alric, L., Cramp, M. E., Donfield, S. M., Edlin, B. R., Tobler, L. H., Busch, M. P., … Thomas, D. L. (2013). Genome-wide association study of spontaneous resolution of hepatitis C virus infection: data from multiple cohorts. Annals of internal medicine, 158(4), 235–245. https://doi.org/10.7326/0003-4819-158-4-201302190-00003
- van Manen, D., van ‘t Wout, A.B. & Schuitemaker, H. Genome-wide association studies on HIV susceptibility, pathogenesis and pharmacogenomics. Retrovirology 9, 70 (2012). https://doi.org/10.1186/1742-4690-9-70
- Klebanov N. (2018). Genetic Predisposition to Infectious Disease. Cureus, 10(8), e3210. https://doi.org/10.7759/cureus.3210