How does Corona Virus compare with seasonal Influenza?

Question

Several of my students have asked me about this, and I welcome comments and answers from others with up-to-date information.

Answer 1

The first thing to understand about coronaviruses are that they are an entirely different family of virus compared to seasonal influenza. Influenza A or B are typically the agents responsible for the seasonal flu, and are members of the orthomyxoviridae family. The 2019 coronavirus (COVID-19) is part of the larger coronaviridae group.

In terms of symptoms, the seasonal flu typically presents as a fever, headache, body pain, and of course cough, sore throat, and runny nose. The single biggest complication of the flu is the potential for a superimposed bacterial pneumonia, which can be quite severe. The influenza virus is transmitted via airborne particles from affected individuals coughing and sneezing. As you may know, there is a medication called Tamiflu (oseltamivir) we can use to shorten the course of the illness.

As far as symptoms of COVID-19 are concerned, the way this presents is as a primary pneumonia, which manifests as fever, cough, and trouble breathing. One way to confirm pneumonia is to do a chest X-Ray which will show haziness in the lungs. As you can see, what concerning is the overlap of the symptoms of the flu and COVID-19. Both viruses are also transmitted via aerosols. However there is good news. The 2019 coronavirus is not inherently deadly, as about 80% of cases will only manifest as a mild pneumonia, meaning most healthy people should be able to cope just fine. Currently we do not have a medicine to help fight this virus.

One way to differentiate these 2 viruses clinically is to perform a nasal swab to test for influenza A or B. This is a rather simple test that is available in most urgent care settings. If an individual presents with flu-like symptoms and is negative for the flu, and also has a concerning history, then we would start to consider something like coronavirus. With that said, proper hand hygiene and respiratory precautions should help to curtail the spread of both of these viruses!

Answer 2

Interesting question. I've listed a few epidemiology-based statistics, but have added links for further reading. This is because as it will be hard to compare the two viruses across every dimension (such as viral features, history of prior outbreaks, complications, et cetera.)

However, I'm guessing you're interested in the case and mortality rates.

COVID-19

- Positive-sense, single-strand RNA virus, enveloped with helical symmetry

- Droplet-based transmission (airborne precautions recommended, as our knowledge of the disease is still growing)

- Approximately 70,000+ cases worldwide.

- Approximately 14% of cases are severe

- Death rate statistics still being collected.

- Overall case-fatality rate is 2.3 percent. Most of these patients had advanced age or underlying medical issues.

Seasonal influenza (orthomyxovirus)

- Negative-sense, single-stranded RNA virus, enveloped with helical symmetry

- 8 segments, pre-disposing the virus to undergo genomic shift

- Droplet-based transmission

- Pandemics include: 1918 ("Spanish flu"), H1N1 ("Swine flu"), H3N2, H7N9 ("Avian flu")

- Influenza outbreaks:

- Outbreaks can last 2-3 months, peaking at ~2-3 weeks

- Attack rate of 10-20% (can be >50% in pandemics)

- Mortality is approximately:

-0.1 - 6.4 deaths / 100,000 individuals <65

-2.9-44.0 deaths / 100,000 individuals 65-74

-17.9-223.5 deaths / 100,000 individuals >75

From the above statistics, you can see that the death rate appears to be greater in the COVID-19 population. However, this is not a perfect comparison as the COVID-19 data was not stratified according to age. We'll have to await more data. Both viruses are respiratory illnesses which exhibit droplet-based transmission and will have more severe effects in the elderly, immunocompromised, and those with medical illness.

Additionally, while the general population is less vulnerable to influenza (owing to the flu vaccine and herd immunity), COVID-19 is new and thus people are less likely to have immunity.

Sources:

https://www.uptodate.com/contents/epidemiology-of-influenza

https://www.uptodate.com/contents/coronavirus-disease-2019-covid-19

Answer 3

The Corona Virus, also known as 2019-nCoV,SARS-CoV-2 shortened to Covid-19 originated in Wuhan, China. It likely started in bats (which are mammals), but is also likely found in cows and cats. The presenting symptoms almost always include fever, dry cough, and dyspnea (shortness of breath). Of the reported 81,000 plus cases (the actual number is believed to be much higher), there have been over 2,700 reported deaths, mostly in China, South Korea, Japan, and Iran. The reported case fatality rate is 3.4% but may actually be lower due to a shortage of diagnostic kits and under-reporting of mild illness.

Seasonal influenza, on the other hand, presents with fever, dry cough, and myalgias (aches and pains), and often nasal congestion. According to the Centers for Disease Control (www.cdc.gov), there have been approximately 32 million cases of influenza this season, with 310,000 hospital admissions and 18,000 deaths, with an estimated fatality rate of 6.4%.

So far, influenza, in an average flu season like this one, is far more serious, particularly if you live in the US.

The best and most current information is available on the CDC website, CDC.gov, and is updated continuously with the latest data and recommendations from the experts.

Answer 4

Death Rate:

Death rate statistics will continue to be collected.

Globally, 101,781 cases of COVID-19 have been confirmed. Of the confirmed cases, 3,460 people have died; thus, the current death rate is 3.40%. (Washington Post, 2020).

In the U.S. there are more than 1400 confirmed cases of COVID-19; of these cases, 14 have died (Washington Post, 2020).

Concerning influenza and pneumonia, 14.9 people die per 100,000 population (KFF, 2020).

Noteworthy:

Scientists discovered that coronavirus COVID-19 has mutated into two strains: 'L' and 'S' types. The L-type accounts for 70% of cases and appears to be far more aggressive. This discovery could hinder attempts to develop a vaccine (Tang et al, 2020; Knapton, 2020).

References (4)

Kaiser Family Foundation. (2020). Number of Deaths per 100,000 population caused by influenza and pneumonia. Retrieved from https://www.kff.org/other/state-indicator/influenza-and-pneumonia-death-rate/

Knapton, S. (2020). Coronavirus has mutated.... Retrieved from https://www.telegraph.co.uk/science/2020/03/04/coronavirus-has-mutated-aggressive-disease-say-scientists/

Tang X., Wu W., Li X., Song Y.,.....Lu J. (2020). On the origin and continuing evolution of SARS-CoV-2, National Science Review. Retrieved from https://doi.org/10.1093/nsr/nwaa036

Washingtonpost (2020). Mapping the spread of the coronavirus in the U.S. and worldwide. Retrieved from https://www.washingtonpost.com/world/2020/01/22/mapping-spread-new-coronavirus/