Why COVID-19 is Worse Than the Flu

Why COVID-19 is Worse Than the Flu

  • This page was last updated at July 03, 2020.

The current coronavirus pandemic has brought the world to a stop. The pandemic has caused hundreds of thousands of casualties, a paralyzed world economy, and current social restrictions. 

Despite these, countless people still cannot fathom the proportions of this pandemic. The utter disbelief has spurred panicked acquisition of products like face masks, gloves, thermometers, and hand sanitizer.

Many are those who underestimated the novel coronavirus when it had first appeared, comparing it to a simple case of the flu. Despite what the world has come to today, several people still hold that assumption.

The novel coronavirus vs the flu is a much greater threat. To truly appreciate how menacing this COVID-19 outbreak is, let’s take a closer look at both illnesses.

COVID-19 vs Flu

Both the flu and COVID-19 are caused by viruses. The flu is usually used as an umbrella term that encompasses most respiratory infections. However, it refers to one particular respiratory illness caused by a group of viruses known as Influenza.

The flu is most often seasonal, with high rates of infection usually reported between December and February. In other rare cases, the flu can cause a pandemic situation, albeit less severe than the novel coronavirus [1].

A pandemic is defined as an outbreak of a disease affecting a high proportion of the population or spread over wide areas, crossing international boundaries [2]. Only a few instances of a flu pandemic have been reported over the past centuries, with the most recent one being the 2009 H1N1 swine flu pandemic. Almost a century earlier, in 1918, the H1N1 strain of Influenza was also responsible for one of history’s deadliest pandemics: the Spanish Flu.

Coronavirus, on the other hand, refers to a group of viruses known to cause the common cold in humans. In recent years, new and more dangerous strains of these viruses have emerged, causing more serious respiratory conditions [3]:

  • SARS-CoV: is a variation of the Coronavirus responsible for the Severe Acute Respiratory Syndrome (SARS) epidemic that lasted from 2002 to 2004.
  • MERS-CoV: is another strain that appeared in the Middle East in 2012, causing an acute respiratory syndrome in infected people.
  • SARS- CoV-2: is the scientific name of the novel coronavirus that is responsible for the recent COVID-19 outbreak, which started in China in December 2019.
The questions surrounding the mechanism of the emergence of these viruses have not been answered, but one thing is certain, they are highly contagious. SARS-Cov-2 or the novel coronavirus is particularly so. The high contagion rate of the novel coronavirus is one of the most important factors that allowed it to cause so much damage in so little time.

Coronavirus vs Flu Transmission

The flu and the COVID-19 share the same modes of transmission. Respiratory viruses are present in saliva droplets, which can cause infection either through direct contact (by kissing an infected person for example) or indirect contact (by shaking hands with an infected person).

Short-range droplet transmission is also possible, and it can happen when an infected person talks, coughs or sneezes in front of an uncontaminated individual.

According to current evidence, the World Health Organization does not believe airborne transmission to be a possible mode of transmission for the novel coronavirus [7].

However, recent studies have found the novel coronavirus to be able to linger in the air for up to 3 hours [8], making the possibility of airborne transmission more likely.

In light of these findings and the current evolution of the outbreak, many scientists are pressing authorities to declare the novel coronavirus as an airborne disease and to provide clear guidelines for optimal ventilation as a preventive measure.

COVID-19 Contagion Rate

The contagion rate of the coronavirus in comparison to the flu is one of the reasons why the coronavirus is far more dreadful.

The contagion rate of viruses is measured by the basic reproduction number referred to as R0, which is pronounced R naught or R zero. R0 is defined as the expected number of cases directly caused by one infected case in a population where all individuals are susceptible to infection [4].

The value of R0 refers to the potential of one infected person to contaminate other people. The higher the R0 value, the more contagious and therefore more dangerous a virus is.

The R0 value of the seasonal flu is accepted to range from 0.9 to 2.1 [5]. The R0 of more virulent flu strains, like the one responsible for the 2009 swine flu pandemic was measured to be between 1.4 and 1.6 [5].

The basic reproduction number of the novel coronavirus is concerning, to say the least. A new study recently published estimated the R0 value of the novel coronavirus to be 5.7 [6], making it three to four times more contagious than the flu.

Coronavirus vs Flu Immunity

People aren’t immune to the novel coronavirus because it didn’t exist before. This adds to the sensitivity of the situation because the only way to truly overcome this outbreak is to gain immunity, either naturally by coming into contact with the virus and getting sick or through vaccination. While you can be vaccinated against the flu, there is currently no vaccine against the novel coronavirus.

One may argue that flu pandemics are also caused by viruses that didn’t exist before, but these pandemics can be less severe because some people may be immune to the new virus strain which is not quite as genetically different as so-called “novel” strains.

This was the case in 2009 during the H1N1 flu pandemic where older people were found to be immune to the new H1N1 strain because they had come into contact at some point in their lives with a similar flu virus [9]. Some virus strains have similar genetics that imparts more broad immunity, while novel strains like COVID-19 are very genetically different from other coronaviruses.

Coronavirus vs Flu Symptoms

Both the flu and COVID-19 share some common symptoms, which may explain the existing confusion between the two illnesses.

The flu can present as fever, fatigue, generalized muscle aches, cough, sore throat, congestion, and headaches. It can be quite unpleasant, but it is mostly benign because the virus attacks the upper respiratory tract, which consists of the nasal passages, sinuses, pharynx, and the throat.

Accounts of pneumonia caused by the flu are possible but rare, mostly happening in people with a compromised immune system, or during flu pandemics where the virus strain is more virulent. The fact that the flu doesn’t usually damage the lungs is a very important detail because the novel coronavirus does quite the opposite.

A coronavirus infection can have no sign at all, making the person highly contagious since they ignore that they are infected. It can cause mild symptoms like headaches, fever, and a dry cough, but it can also cause severe pneumonia.

As opposed to the seasonal flu which rarely causes pneumonia, in COVID-19; pneumonia is the most frequent serious manifestation [10]. The novel coronavirus is more severe than the flu because it is more likely to infect the lower respiratory tract, destroying both lungs, causing respiratory failure, and subsequently death.

Another key element in comparing both viruses lies in the illnesses that they cause. If the flu is well known by scientists and doctors, with readily made treatment plans to follow and thousands of published studies citing the complications to anticipate; COVID-19, on the other hand, is quite new.

The world has been battling the flu for centuries, and as a result, Medicine has gotten quite good at it. COVID-19 has only appeared this past December, which means that we are still learning about the virus as we are battling it, and that makes it even more dangerous.

Additionally, if COVID-19 has been initially thought of as a respiratory disease, recent studies have shown that it can also damage the neurological system. Many cases have been reported of nerve damage caused by the novel coronavirus, like the sudden loss of smell most likely caused by an inflammation of the olfactory nerves [11]. Cases of COVID-19 associated brain hemorrhage have also been reported [12].

Coronavirus vs Flu Deaths

According to the CDC, from October 1st, 2019 to April 4th, 2020, there have been a total of 24,000 to 62,000 deaths in the United States caused by the flu [13]. These numbers are spread over 6 months, which represents this year's flu season.

Coronavirus, on the other hand, has caused a total of 73,566 deaths in the United States as of May 7th, according to Johns Hopkins University [14]. The total coronavirus related deaths have only occurred over three months since the first US coronavirus case had been confirmed in late January. These coronavirus vs flu statistics not only show that the coronavirus numbers are higher than those of the flu, but they have also taken place in a shorter period which means that the novel coronavirus is deadlier than the flu.

Coronavirus vs Flu Impacts

Aside from the unfortunate number of casualties and confirmed cases, the novel coronavirus outbreak has also impacted the world in other dimensions.
The current fear-fueled media frenzy adds to the stress of the situation, which is likely to impact the mental health of the general population. First responders, medical professionals, and authorities have also been under insane amounts of pressure and stress for a long time, which may cause them to experience post-traumatic stress disorder in the future, just like what had happened in 2003 during the SARS outbreak [15].

Although past pandemics like the Spanish flu were deadlier, no past outbreak has ever affected the world economy the way the novel coronavirus has.

Both micro and macroeconomics are suffering because of the outbreak. In communities, small businesses have closed, manual labor workers are jobless and people in industries related to leisure and tourism are on standby, ignoring their fate. International airlines are on the verge of bankruptcy, stocks are crashing and the world is simply watching as the global economy is falling apart.

Even after the sanitary crisis state is lifted, we are likely to battle the socio-economic consequences of the coronavirus outbreak for many years to come. For all we know, the world may never be the same again after this.

Final Thoughts on the Difference Between COVID-19 and the Flu

The impact and the ramifications of the novel coronavirus greatly surpass those of the flu. As the world slowly prepares to lift the social restrictions and transition out of quarantine, it is now more important than ever, to understand that the coronavirus is a lot worse than the flu.


  1. CDC. (2019, May 7). How Is Pandemic Flu Different from Seasonal Flu?
  2. WHO. (2011). The classical definition of a pandemic is not elusive.
  3. Khan, S., Siddique, R., Shereen, M. A., Ali, A., Liu, J., Bai, Q., … Xue, M. (2020). Emergence of a Novel Coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2: Biology and Therapeutic Options. Journal of Clinical Microbiology, 58(5). 
  4. Fraser C, Donnelly CA, Cauchemez S, et al. Pandemic potential of a strain of influenza A (H1N1): early findings. Science. 2009;324(5934):1557‐1561. 
  5. ‌Coburn BJ, Wagner BG, Blower S. Modeling influenza epidemics and pandemics: insights into the future of swine flu (H1N1). BMC Med. 2009;7:30. Published 2009 Jun 22. 
  6. Sanche, S., Lin, Y. T., Xu, C., Romero-Severson, E., Hengartner, N., & Ke, R. (2020). High Contagiousness and Rapid Spread of Severe Acute Respiratory Syndrome Coronavirus 2. Emerging Infectious Diseases, 26(7). 
  7. World Health Organization: WHO. (2020, March 29). Modes of transmission of virus causing COVID-19: implications for IPC precaution recommendations
  8. NIH. (2020, March 17). New Coronavirus Stable for Hours on Surfaces
  9. Xu R, Ekiert DC, Krause JC, Hai R, Crowe JE Jr, Wilson IA. Structural basis of preexisting immunity to the 2009 H1N1 pandemic influenza virus. Science. 2010;328(5976):357‐360. 
  10. ‌Wang, D., Hu, B., Hu, C., Zhu, F., Liu, X., Zhang, J., ... & Zhao, Y. (2020). Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus–infected pneumonia in Wuhan, China. Jama, 323(11), 1061-1069. 
  11. Reinhard, A., Ikonomidis, C., Broome, M., & Gorostidi, F. (2020). Anosmia and COVID-19. Revue medicale suisse, 16(691-2), 849. 
  12. ‌Poyiadji, N., Shahin, G., Noujaim, D., Stone, M., Patel, S., & Griffith, B. (2020). COVID-19–associated acute hemorrhagic necrotizing encephalopathy: CT and MRI features. Radiology, 201187. 
  13. CDC. (2020, April 17). 2019-2020 U.S. Flu Season: Preliminary Burden Estimates
  14. Wu P, Fang Y, Guan Z, et al. The psychological impact of the SARS epidemic on hospital employees in China: exposure, risk perception, and altruistic acceptance of risk. Can J Psychiatry. 2009;54(5):302‐311.