Monday, 30th October 2017

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What is the difference between coronavirus and seasonal flu?

In many ways, the flu is the best argument for throwing everything at the coronavirus

By Denise Grady/The New York Times News Service
  • Published 24.03.20, 11:37 PM
  • Updated 24.03.20, 11:37 PM
  • 3 mins read
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In both flu and the illness caused by the coronavirus, people may be contagious before symptoms develop, making it difficult or even impossible to control the spread of the virus (iStock photo)

Is this new coronavirus really a serious danger? Doesn’t the flu kill more people? Yes, the flu is terrible — that’s exactly why scientists don’t want another contagious respiratory disease to take root. In many ways, the flu is the best argument for throwing everything at the coronavirus. Here’s a closer look at the similarities and differences.

Which virus is deadlier?

The coronavirus seems to be more deadly than the flu — so far. On average, seasonal flu strains kill about 0.1 per cent of people who become infected. The 1918 flu had an unusually high fatality rate, around 2 per cent. Because it was so contagious, that flu killed tens of millions of people.

Early estimates of the coronavirus death rate from Wuhan, China, the epicentre of the outbreak, have been around 2 per cent. But a new report published in The New England Journal of Medicine, finds a lower rate: 1.4 per cent. The coronavirus death rate may be even lower, if — as most experts suspect — there are many mild or symptom-free cases that have not been detected.

The true death rate could turn out to be similar to that of a severe seasonal flu, below 1 per cent, according to an editorial published in the journal by Dr Anthony S. Fauci and Dr H. Clifford Lane, of the National Institute of Allergy and Infectious Diseases, and Dr Robert R. Redfield, director of the Centers for Disease Control and Prevention.

But even a disease with a relatively low death rate can take a huge toll if enormous numbers of people catch it.

More contagious?

So far, the new coronavirus seems to be more contagious than most strains of the flu, and roughly as contagious as strains that appear in pandemic flu seasons. Each person with the coronavirus appears to infect 2.2 other people, on average. By comparison, the figure for the seasonal flu is roughly 1.3.

In both flu and the illness caused by the coronavirus, people may be contagious before symptoms develop, making it difficult or even impossible to control the spread of the virus. Nobody knows how many people infected with the coronavirus have mild symptoms or none at all.

Who is most at risk?

Both the coronavirus and influenza are most dangerous to people who are older than 65, or have chronic illnesses or a weak immune system. Death rates among men infected with the coronavirus in China, particularly those in their late 40s and older, have exceeded those among women, a pattern not seen in the seasonal flu. The reason for the discrepancy is not known, although Chinese men do smoke more, often resulting in compromised lung function. There seems to be another important difference: the flu appears far more dangerous to children, particularly very young ones. Children infected with the new coronavirus tend to have mild or no symptoms.

Which makes you sicker?

Hospitalisation rates among children and young adults with flu this year have been unusually high. Most people recover in less than two weeks.

Most cases of coronavirus infection are not severe, but some people do become quite sick. Data from the largest study of patients suggests that of coronavirus patients receiving medical attention, 80 per cent had mild infections, about 15 per cent had severe illnesses, and 5 per cent were critical. The first symptoms, fever and cough, are similar to that of the flu, so the diseases can be hard to tell apart without a test. Pneumonia is common among coronavirus patients, even among those whose cases are not severe.

Are treatments available?

There is no approved antiviral drug for the coronavirus, though several are being tested. Doctors recommend the usual: rest, medicine to reduce pain and fever, and fluids to avoid dehydration.

For the flu, however, there are four prescription medicines. All work best if taken within a day or two of when symptoms start.

Can I get vaccinated?

An experimental vaccine for the coronavirus may be ready for testing in humans within months, but will take much longer, at least a year or two, to become available for widespread use.

Flu vaccines, on the other hand, are widely available and generally 40-60 per cent effective, which means they will reduce cases by that amount in a population that has been vaccinated.