“Comparison is the death of joy.”

Mark Twain

With fears about the Coronavirus epidemic spreading like, well, an epidemic, the public response to the virus has ranged from complete apathy to full on panic. Face masks are flying off the shelves, “I survived Coronavirus” t-shirts and “Coronavirus protection kits,” are being sold on E-Bay, and a virus-themed outbreak game called Plague Inc. is hitting record numbers on its app. There is a plague of misinformation on the Internet, and one of the most frustrating aspects is the constant conflation of the flu and Coronavirus. They are two distinct diseases, with very different epidemiological profiles, but it has become wildly popular to compare the two. Some articles point out that the Flu infects millions of people every year, dwarfing the Coronavirus outbreak. Others argue that Coronavirus is both more deadly and more novel. At its most basic, the comparison is meaningless; a juxtaposition of apples on oranges. But since comparisons are running rampant, let’s make sure we’re getting the facts straight.

Virology

The Coronavirus causing the current outbreak, recently named COVID-19 by the WHO, is not the only Coronavirus in existence. It’s not even the only one that can infect people. Named for the crown-like spikes covering the viral surface, most Coronaviruses reside in animals but there are seven types that can infect people. Most of these Coronaviruses are very common, and usually cause no more than a mild-to-moderate upper respiratory infection, not unlike the common cold. However, some Coronaviruses have been known to cause outbreaks, including the Middle East Respiratory System Coronavirus (MERS) and its better-known cousin Severe Acute Respiratory System Coronavirus, or SARS. COVID-19 is the seventh Coronavirus known to infect humans and was only recently discovered.

There are four types of flu viruses – A, B, C and D – though A and B are the most common causes of human illness. Within these two types, there is a dizzying variety of subtypes, lineages, clades and sub-clades, determined by the viral proteins. There have been several killer flu pandemics over the last century, including the Spanish Influenza of 1918, the Asian Influenza of 1957, the Hong Kong Influenza of 1968 and the Swine Flu of 2009.

Signs and Symptoms

Both Coronavirus and Flu viruses cause an upper respiratory illness characterized by fever, cough, fatigue, muscle pain, shortness of breath, even diarrhea and nausea. Transmitted through respiratory droplets, both viruses spread easily from person to person. Both diseases can progress to pneumonia, kidney failure, and even death.

Treatment and Prevention

The flu vaccine is based on the varying proteins on the viral surface. Every year, scientists utilize epidemiologic studies every year to try to determine which strains to include in the vaccine. A recent study by the CDC showed that the flu vaccine was about 40% effective in preventing severe enough flu symptoms to need to see a doctor. But the vaccine has other benefits, including preventing and reducing the severity of complications. Coronaviruses have no known vaccine. Scientists are currently working on a vaccine for COVID-19, but it won’t be ready for at least a year.

Treatment for both Coronavirus and Influenza is mostly supportive, with respiratory support given if necessary. Antiviral medication such as Tamiflu, has been shown to speed up recovery in patients with the flu. Such results have not been demonstrated in COVID-19, yet some patients continue to receive it.  

Transmission

COVID-19 is incredibly contagious. While studies have really just begun, initial estimates show that each person infected could spread the virus to 1.5-3.5 other people without effective preventive measures. In contrast, people with the seasonal flu tend to infect only 1.3 other people. While this may not seem like a large difference, it can lead to a drastic increase in the total number of people infected. Furthermore, COVID-19 has a longer incubation period, which allows for increased transmission. Most people with the Flu exhibit symptoms within 2-4 days of infection. With Coronavirus, it can take as much as 2 weeks from infection to first symptoms. The patient is contagious and spreading the virus that whole time. However, risk of transmission can be decreased with effective public health measures, such as isolation and hand-washing.

Epidemiology

As of February 13th, 2020 there are over 59,804 confirmed cases of COVID worldwide, with 1367 deaths, according to China’s National Health Commission. Most of those are in Hubei Province, China – the Province containing the outbreak’s epicenter, Wuhan – but the disease has now spread to 25 countries, including the USA. This puts the fatality rate of Coronavirus at 2.2%. However, many believe the NCP’s mortality rate may increase as the disease continues to spread. A recent JAMA study of patients in Wuhan found a mortality rate of 4.3% and rapid person-to-person transmission5. Older patients and those with multiple comorbidities were the most likely to be the most seriously affected.

Every year, influenza affects somewhere between 3-11.3% of the US population; a staggering 27 million people. The mortality rate varies widely from year to year. In the 2017-2018 season, a particularly nasty outbreak caused more than 80,000 deaths. In previous decades, the average was 56,000. This means the recent mortality rate was somewhere between 02.-0.3%, less than 1/10th of the current estimate for Coronavirus.

Two diseases: one preventive strategy.

COVID-19 and Influenza are two viral respiratory diseases that are at once very similar and quite different. Both need to be taken seriously. COVID-19 has a high mortality rate, is easily transmissible through respiratory droplets, and has no known vaccine or specific treatment. So far, it has only killed a relatively small number of people, but scientists are not sure how this outbreak may evolve over time. If you live in the US and do not work in healthcare, your chance of coming into contact with COVID-19 is exceedingly small. Influenza, on the other hand, has a relatively low mortality rate, but is exceedingly prevalent, so it kills tens of thousands of people every year in the US alone. Luckily, there is a vaccine that can both prevent the disease and reduce severity of complications, as well as a targeted treatment that helps to speed up recovery. No matter where you live in the world, you are likely to encounter some strain of influenza this winter. So whether you’re trying to avoid the Flu or worried about a global worsening of COVID-19, your standard precautions remain the same. Wash your hands, cough into your elbow, and don’t go to work if you feel sick. And get your flu shot. After all, an ounce of prevention is worth a pound of cure.  

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