03—MAY—2021 14:09 GMT
ithin the past year of living in a pandemic, whenever you feel a slight sore throat, runny nose, cough, or fever, I’m sure we’ve all been in the same position of thinking, ‘could this be an allergy or am I overthinking it?’ It might just be a cold, or could it be I’ve got coronavirus?’. With several overlapping symptoms, it is not surprising that it can be a challenge to figure out what that runny nose could be without proper investigations.
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So what makes COVID-19 so “special” from the flu or common cold that has been around for decades?

Thinking Homer, from The Simpson's.
Image from Google image.
Whilst we know that the symptoms of COVID-19 can range from being completely asymptomatic (which made the spread of this disease incredibly rapid) to becoming so severe that some patients require ventilator support - the most common symptoms experienced by patients are fever, sore throat, body aches, headaches, and fatigue.
However, these symptoms are sensitive but not specific. Meaning, it is easy to tell that you have an ongoing respiratory infection (which can be caused by a bacteria, virus, fungus or parasite) but they can’t really tell WHAT is causing it.

Difference between sensitivity and specificity.
Courtesy of PTStudyGuide
The graph below illustrates the percentage of inpatients who reported the symptoms listed. As shown, the proportion of patients who reported loss of smell and taste are significantly lower. This means that the average person may present or think they have the usual respiratory tract infection, or an infection of the digestive tract such as acute gastroenteritis - without realising that they may actually have COVID.

Graph 1. Prevalence of COVID-19 symptoms



Table 1. Similarities and differences between COVID-19, flu and cold
To learn more about case fatality rates and infection fatality rates : https://www.who.int/news-room/commentaries/detail/estimating-mortality-from-covid-19
References
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Coronavirus disease (COVID-19): Similarities and differences with influenza. Who.int. (2020). Retrieved 19 January 2021, from https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/coronavirus-disease-covid-19-similarities-and-differences-with-influenza
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Key Facts About Influenza (Flu) | CDC. Cdc.gov. (2019). Retrieved 19 January 2021, from https://www.cdc.gov/flu/about/keyfacts.htm.
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Roser, M., Ritchie, H., Ortiz-Ospina, E., & Hasell, J. (2021). Coronavirus (COVID-19) Deaths - Statistics and Research. Our World in Data. Retrieved 19 January 2021, from https://ourworldindata.org/covid-deaths.
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Roser, M., Ritchie, H., Ortiz-Ospina, E., & Hasell, J. (2021). Mortality Risk of COVID-19 - Statistics and Research. Our World in Data. Retrieved 19 January 2021, from https://ourworldindata.org/mortality-risk-covid.
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Similarities and Differences between Flu and COVID-19. Centers for Disease Control and Prevention. (2020). Retrieved 19 January 2021, from https://www.cdc.gov/flu/symptoms/flu-vs-covid19.htm.