Coronavirus: The Pandemic in Context

On January 30, 2020, the spread of a novel strain of coronavirus (nCov) was declared a global health emergency by the World Health Organization (WHO). The outbreak began in Wuhan—the capital city of China's Hubei province—back in December 2019.

When this blog was published in early February, world health officials were still referring to this outbreak as an epidemic. On March 11, however, the World Health Organization declared the novel coronavirus—now commonly referred to as COVID-19—a global pandemic. There are nearly 4.5 million worldwide cases of COVID-19 confirmed as of May 15, with 1.4 million confirmed cases in the U.S. alone. 

What is Coronavirus?

According to the Centers for Disease Control and Prevention (CDC), coronaviruses are a common family of viruses that generally cause mild to moderate upper-respiratory illnesses. These illnesses are zoonotic meaning they’re transmitted via contact with infected animals. Some recognizable coronaviruses include severe acute respiratory syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS). 

Coronavirus diagnosis volumes, 2019

Fig 1 Data from Definitive Healthcare’s hospital inpatient diagnosis analytics feature in the Medical Claims database. Full-year 2019 hospital claims sourced through multiple clearinghouses. Accessed January 30, 2020. 

The first case of SARS, which originally appeared in 2002, was transmitted from civet cats. There have been no known transmissions of this virus since 2004. Its cousin, MERS, was originally transmitted to humans from dromedary camels. MERS first appeared in 2012, with a second outbreak recorded in 2015, but has since become extremely rare. 

Respiratory illnesses by diagnosis volume, 2019 

Fig 2 Data from Definitive Healthcare’s hospital inpatient diagnosis analytics feature in the Medical Claims database. Full-year 2019 hospital claims sourced through multiple clearinghouses. Accessed January 30, 2020. 

How is the new Coronavirus (nCOV) different? 

In early February, the CDC released information about COVID-19 symptoms in order to promote public awareness about this new virus. According to this information, the symptoms present much like those of other coronaviruses like SARS and MERS—meaning that patients are likely to experience fever, cough, shortness of breath, difficulty breathing and, in severe cases, pneumonia in one or both lungs.

Since this information was first released, some patients have presented with new COVID-19 symptoms including loss of taste or smell, skin rashes like "COVID toes," or gastrointestinal symptoms like nausea, vomiting, and diarrhea. In addition, an increasing number of children and young people have become infected with the virus—despite earlier claims that young people were somewhat less susceptible to COVID-19. 

Until more recent data became available, many experts argued that the common flu was a more pressing respiratory concern than the new coronavirus. Though we now know that COVID-19 spreads more easily and has a higher mortality rate than seasonal influenza, the CDC estimates that between 39 and 56 million Americans have been diagnosed with the flu from October 2019 through April 2020. Of these, more than 410,000 have been hospitalized and more than 24,000 have died.  

Last flu season, which ran from October 2018 through March 2019, the flu caused roughly 34,000 deaths. Experts speculate the flu is responsible for between 12,000 and 61,000 deaths in the U.S. each year, depending on the severity of the season. 

Influenza diagnosis volumes, 2019 

Fig 3 Data from Definitive Healthcare’s hospital inpatient diagnosis analytics feature in the Medical Claims database. Does not include diagnosis volumes for influenza-related complications such as pneumonia. Full-year 2019 hospital claims sourced through multiple clearinghouses. Accessed January 30, 2020. 

Coronavirus versus past epidemics 

Many viral outbreaks and pandemics reach the U.S., but few have caused as severe or lasting damage to the population as COVID-19 has. For comparison, we’ve compiled intelligence from some of the most well-known epidemics of the past decade: Zika, Ebola, and H1N1. 

Zika diagnoses by claim year 

Before the novel coronavirus, Zika was the most recent pandemic outbreak to impact the United States. The most recent Zika outbreak was first reported in Brazil in May of 2015, and was declared a public health emergency by January 2016.

Fig 4 Data from Definitive Healthcare’s comprehensive Medical Claims database. Historical claim data only available from 2016 forward and pulled via Professional Services. Only includes principal diagnoses. Accessed January 31, 2020. 

Ebola diagnoses by claim year 

The 2014 Ebola outbreak, which began in West Africa, was the largest in recorded history. Ebola was originally identified in 1976 but saw a dramatic resurgence in 2014.

This is largely due to the epidemic’s origins in countries with weaker healthcare systems and lower incomes. In large rural areas without comprehensive healthcare coverage, communities are more likely to become overwhelmed by illness before patients can access proper treatment. 

Between August 2014 and March 2016, more than 30,000 people worldwide were infected with Ebola—with as many as 11,000 reported deaths. An additional Ebola emergency was declared last year, with an outbreak beginning in the Democratic Republic of the Congo. 

Fig 5 Data from Definitive Healthcare’s comprehensive Medical Claims database. Historical claim data only available from 2016 forward and pulled via Professional Services. Only includes principal diagnoses. Accessed January 31, 2020. 

H1N1 (Swine Flu) diagnoses by claim year 

The H1N1 virus, colloquially known as “swine flu,” took hold in 2009. Reported deaths from the disease ranged from 123,000 to more than 575,000 globally. Human H1N1 infections declined drastically after October 2009, and is no longer considered a pandemic—it is, however, a regular human flu virus that circulates seasonally worldwide.

Fig 6 Data from Definitive Healthcare’s comprehensive Medical Claims database. Historical claim data only available from 2015 forward and pulled via Professional Services. Only includes principal diagnoses. Accessed January 31, 2020. 

Originally published February 4, 2020 and updated based on information available as of May 15, 2020 to reflect changes in international impact and total number of diagnoses.