The Differences and Similarities Between Influenza and COVID-19

At the height of the current global health emergency brought on by SARS-CoV 2 that causes COVID-19, New Hope Unlimited implemented a new crisis management plan to minimize the risks of infection for our patients and staff.

Furthermore, we understand that some cancer patients are more vulnerable to infections and diseases such as COVID-19.

Given the current public health emergency, we believe that it is essential for us to carefully assess our patients’ condition so we can provide the best care possible, which includes educating them.

What is a Coronavirus?

For the record, coronavirus is not a single type of virus, but rather a large family of viruses that are RNA related. Most people use the term coronavirus for the health emergency that we are dealing with right now, but experts and professionals would rather use SARS-CoV2 to address the virus that is currently infecting thousands.

The pandemic that we are currently facing is caused by a newly discovered virus (2019 novel coronavirus) which is named Severe Acute Respiratory Syndrome – CoronaVirus 2 or SARS-CoV 2. In other words, the CoronaVirus Disease 2019 or COVID 19 for short, is caused by the SARS-CoV 2 viral strain that is under the coronavirus family. 

Not every strain of viruses that are under the coronavirus family can cause COVID-19. Some human coronaviruses are more common in our environment including, HKU1 (beta coronavirus), and OC43 (beta coronavirus), both of which can cause common colds and/or upper respiratory conditions. Contracting the aforementioned types of coronaviruses would not necessarily give you COVID-19.

Some varieties of coronaviruses aren’t even as fatal and as infectious as the SARS-CoV2. In fact, other coronavirus strains don’t affect humans at all. 

Several classifications of coronaviruses are known to infect camels, bats, cattle, and even fowls like turkey. In rare cases, coronaviruses from mammals and birds can mutate or perform a host jump (cross-species contamination) to infect humans and cause new diseases such as COVID-19.

Other infamous types of coronaviruses include the Middle-Eastern Respiratory Syndrome-related CoronaVirus (MERS-CoV), and Severe Acute Respiratory Syndrome (SARS-CoV-1, during 2003).


Previously called 2019 novel coronavirus or 2019-nCoV, it is a type of positive-sense single-stranded RNA virus that is believed to be of zoonotic origins.

Zoonotic viruses like SARS-COV-2 are capable of cross-species contamination, supporting the majority’s observation that it might have come from bats. SARS-CoV-2 is also observed to have a close similarity to other coronaviruses that live off of bats.

However, studies suggest that the bat coronavirus wasn’t directly passed on from bats to humans. The majority of the researchers believe that before the virus successfully made humans as hosts, an intermediate host like a pangolin, could have led the virus to its initial human transmission.

The first case of COVID-19 in December 2019, in Wuhan, China, has supported that an intermediate host was present because most of the first patients are believed to have gotten it at the Huanan Seafood market.

A live animal market is a great place for viruses and bacterias to thrive, especially if sanitation is not properly observed.

The Influenza Virus

This is the virus that causes the common flu. Hence, it is also referred to as “the flu” virus. There are several types of influenza viruses that can infect humans such as the swine flu in the U.S. and the Avian Flu.

Influenza viruses are classified as Influenza Virus A, B, C, D, which have slightly different characteristics in some ways. All of them are under the virus family Orthomyxoviridae.

Influenza A viruses are the most common influenza virus that can infect birds and humans. Both bird flu (H5N1 of 2004) and swine flu (H1N1 of 2009) are under the influenza A classification.

Although the common flu is commonly transmitted from person-to-person, some influenza viruses like H5N1 and H1N1 can be transmitted from other animals directly to its human host, which could then transmit it to a different individual.

Most Notable Similarities and Differences

COVID-19 that is caused by SARS-CoV-2, has some similarities to the seasonal flu that is caused by certain influenza viruses.


Perhaps the most significant similarity between these two diseases is their symptoms, given that they both cause upper respiratory illness and could both cause pneumonia in severe cases.

Both the flu and COVID19 can cause fever, cough, and fatigue, but in the early stages, COVID-19 causes shortness of breath. While both can also trigger body aches, headaches, and stuffy or runny nose, these latter symptoms are less common for COVID-19 positive patients.


The flu causes typically mild symptoms in a span of a week, but immunocompromised individuals such as some cancer patients may require hospitalization. The rapid onset of the flu symptoms makes it easier to be detected. This way, the infected person may isolate immediately once symptoms start showing.

COVID-19, on the other hand, has a gradual onset for its symptoms. This means that the patient can be asymptomatic (shows no symptoms) for the first 5 days, which could easily get worse in the second week of illness.

Rate of Transmission and Incubation Period

The flu is arguably less contagious than COVID-19, this might be because SARS-CoV-2 can stay in the air for longer periods than the common flu.

COVID-19’s incubation period also lasts much longer at about 7-14 days, while the flu symptoms only last for about 1-4 days.

There’s still a lot to know about SARS-CoV-2 that our experts have yet to unveil. This makes it hard for researchers to come up with a single medicine to treat this disease so they can only treat its symptoms.

In the meantime, comparing COVID-19 to the diseases that we already know may help our medical practitioners in treating its symptoms, and hopefully, soon enough, create a viable vaccine that would help us eradicate this disease and make it less threatening.

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