Covid-19, Influenza and Cold: Differences and Similarities

As respiratory illnesses are found quite common these days, it can be challenging to identify if it's the cold, flu (influenza), or covid, especially when their symptoms often overlap. Since they’re all common respiratory problems, could your sniffles be caused by the COVID-19? Or the Flu? A cold? Or possibly allergies? Let us explore their main differences:

Understanding the differences between Covid, influenza (the flu) and a cold

Essentially, each of these illnesses is caused by varying viruses, but unfortunately share the same similar symptoms. As Covid-19 is a relatively new medical discovery and from time to time exhibits different symptoms, it’s more challenging to tell the difference between Covid-19, the flu, and the cold. Let us walk through the basics.

Covid-19: A contagious severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) and is more serious due to its reported high mortality rate. Its hallmark symptoms include fevers, cough, runny nose, body aches, loss of taste and smell.

Flu (influenza): Also a respiratory illness affecting the lungs that’s caused by the influenza virus such as influenza A or B instead. It is observed annually worldwide and has a seasonal cycle in temperate regions, usually starting May to July and November to January in Malaysia. It is characterized by high fevers, coughing, body aches and other respiratory symptoms. While they seem common, flu can be life threatening, especially for those with underlying medical conditions like heart disease or diabetes. Hence, people with these medical conditions are urged to get vaccinated against the flu every year.

Cold: Caused by many different viruses, but typically a rhinovirus or coronavirus (not the same coronavirus that causes Covid-19). A cold would only affect your upper respiratory tract (nose and throat) and not your lungs. People with colds are more likely to suffer from a runny or stuffy nose than people with flu. They’re usually not that serious and would resolve within a week or two.

The table summarizes how Covid, the flu, and cold differ:

A key difference between all 3 is COVID-19 has a unique symptom associated with it: changes in or complete loss of taste and smell. In addition, COVID-19 typically produces a dry cough, although a cough with phlegm is still seen in some. Compared to the flu, COVID-19 can cause more serious complications in some people.

Besides, sneezing is usually more associated with the common cold than with the flu or COVID-19. In addition, a person with a cold rarely experiences muscle aches, and a cold never causes vomiting or diarrhea.

With such similar symptoms, is there a definitive way of telling if someone has Covid, the flu, or the cold? 

Only with diagnostic testing (ie: covid test kits and influenza testing in health clinics) will one know if he/she has either of the mentioned respiratory illnesses. Specific tests are available for each of these illnesses: 

Covid-19: Polymerase Chain Reaction (PCR) tests and antigen tests that can be found in any community pharmacy are used to detect the presence of the SARS-CoV-2 virus.

Influenza: Influenza testing typically involves PCR tests, rapid antigen tests, and viral culture. 

Common cold: There is generally no specific test for the common cold since it is caused by various viruses. Diagnosis is often established clinically based on presenting symptoms.

Is it possible to have Covid, the flu, and the cold all at the same time? 

Yes, it is possible to be infected with these different viruses simultaneously at a time. When a person is exposed to multiple viruses or bacteria that lead to respiratory infections, they can potentially be infected with more than one of these pathogens at the same time. This may mean their symptoms are more severe and complicated in which medical attention may be needed if not treated properly.

Prevention

To minimize the risk of all respiratory diseases, including allergies, the common cold, and flu as COVID-19, everyone needs to abide by the following preventive measures:

•  Wearing a face mask at all times while in public
•  Frequent handwashing with soap or hand sanitizer
•  Refraining from going to crowded areas and avoiding exposure to suspected or confirmed cases while maintaining social distance. 

Besides, vaccination goes a long way in minimizing the risk of being infected with these vicious viruses. The COVID-19 vaccines are now available to everyone starting from 6 months and above whereas flu shots are available in some clinic appointments.

If you do get the flu, cold or RSV, are you more susceptible to COVID-19?

It’s unlikely that just because you got the flu or RSV you’re more at risk for getting coronavirus or some other viral illness. What you’re exposed to is what you get. With any viral illness, you can develop complications such as bacterial pneumonia, which isn’t spread from person to person but is caused by your own bacteria.

Treatment options

As most virus infections, Covid-19, the flu, and cold are pretty much self-limiting and can be resolved by themselves if not that severe. Nasal decongestants, saline rinses, and pain relievers however can aid with symptomatic relief. Alternatively, you can also:

•  Stay hydrated and drink at least 8 glasses of water a day to replace lost fluids
•  Get plenty of rest
•  Use a cool mist humidifier to help ease congestion and coughing
•  Supplement yourself with Vitamin C and Zinc
•  Limit level and frequency of physical activity

With more severe cases and people with weaker immunity (ie: elderly, pregnant mothers, children, immunocompromised patients) however, antiviral drugs have been approved to help the body fight off the virus, treat the symptoms and reduce the recovery period.

In Summary

While cold, flu, and COVID-19 share some similarities in symptoms and transmission methods, they are distinct illnesses caused by different viruses. Understanding these differences is crucial for accurate diagnosis, appropriate treatment, and effective prevention measures. Regardless of the illness, it's essential to follow public health guidelines, get vaccinated when appropriate, and seek medical advice if you or someone you know experiences symptoms of a respiratory illness.

Stay safe everyone!

This article is written by Janelle Leong, Bpharm(Hons) (DOC2US),
reviewed by Dr. Muhamad Syaqir bin Shukri, MBBS (DOC2US). 

References

1.  https://www.gundersenhealth.org/health-wellness/be-well/how-to-tell-if-you-have-a-cold-the-flu-or-covid-19 

2.  https://www.medicalnewstoday.com/articles/coronavirus-vs-flu#severity-and-mortality 

3.  https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/coronavirus-and-your-health/coronavirus-symptoms-cold-flu-or-coronavirus 

4.  https://www.chla.org/blog/advice-experts/covid-vs-flu-vs-common-cold-vs-rsv-what-you-need-know 

Written by

Janelle Leong, Bpharm(Hons) DOC2US