Many healthy, young people who are exposed to the coronavirus will experience nothing worse than seasonal flu symptoms, or indeed no symptoms at all. This appears to be true but could also be falsely reassuring.

The overall profile of the disease, including its mortality and ability to spread, is now better understood. The health, social and economic impact on large numbers of people means that the disease, COVID-19, is clearly more serious than seasonal influenza.

Calculating mortality in the earlier phases of an epidemic can be deceptive. It was unclear, for example, how many people with mild symptoms in China were not being diagnosed in the first few weeks of February. This could have led to some early overestimation of the mortality rate. However, the extent of this is likely to be small says Bruce Aylward, who led an international mission to China to learn about the virus and the country’s response.

Case fatality rates vary markedly by age, and so population age structure and treatment availability will determine the final rates observed outside China. The “best” estimate of the death rate in known cases (case fatality rate) seems to be from 1% to 4%.  This is likely to be as accurate as anyone can say at the current time and is more than the flu. This still represents a lot of people if the virus spreads, and reinforces the current drive to contain the spread of the virus.

Where did the story come from?

Many mainstream and social media have covered the question of mortality recently including health sites and newspapers. It is well known that “fear stories” in headlines can sell newspapers.

To their credit, most news sources covering death rates reported from the existing outbreak area, and have provided balanced data and facts on this important question, even if the detail lies below the headline or link.

 

What is the basis for the claim?

Dr Aylward , reporting for the WHO, has described the profile of cases in the early stages of the outbreak in China: about 80% of cases were mild, about 14% severe, and about 6% of people became critically ill. The case fatality rate was then between 2% and 4% in Hubei province, and 0.7% in other parts of China, he said.

Seasonal flu, with a case fatality rate of around 0.1% is estimated to kill between 290,000 and 650,000 people a year globally.

 

What do trusted sources say?

Seasonal influenza, pandemic flu (such as H1N1) and SARS, another coronavirus, are natural comparators for these outbreaks, but they are all different diseases with different case fatality rates and profiles.

Seasonal influenza is preventable in more than 70% of people with a vaccine and has low mortality, 0.1% approximately. Because the virus circulates widely in winter months a large number of people can be infected, and those over 65 years or with other health conditions are at higher risk.

The CDC reports that the 2009 H1N1 Pandemic flu, commonly known as swine flu, led to an estimated 151,000 to 575,000 deaths worldwide in 2009. The estimated global death rate was very low at 0.02%.

The European Centre for Disease Prevention and Control reported on the 2002 outbreak of SARS. This disease emerged at the end of 2002 in China and led to more than 8000 cases in 33 countries over a period of eight months. At that time, 10% of people who contracted SARS died.

 

Analysis by EIU Healthcare

 

Citation

  1. Groth L. Is the Coronavirus Worse Than the Flu? Here’s How the 2 Illnesses Compare: It depends on what you mean by “worse” health.com Feb 26, 2020
  2. World Health Organization. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) (accessed March 6th 2020)

Reading list

  1. European Centre for Disease Prevention and Control Situation update for the EU/EEA and the UK, as of 6 March 2020 08:00. Map, epidemiological curves and case counts. (Accessed March 6, 2020)
  2. Huang C. Wang Y. Li X. et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. The Lancet. 2020 January 24. 9. (Accessed March 6, 2020)