As the days go by, a new disease outbreak knocks our doors; you might have heard about COVID-19 or, as is commonly known, coronavirus.
What do we need to know about COVID-19 (coronavirus)?
Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrom (SARS-CoV). A novel coronavirus (nCoV) is a new strain that has not been previously identified in humans.
These viruses are zoonotic, which means that they are transmitted between animals and humans.
The symptoms may include: breathing difficulties, fever, cough and shortness of breath. When severe, the infection may lead to pneumonia, kidney failure and even death.
The visualization here shows this data.
It is most crucial to know the common symptoms: fever and a dry cough.
As the visualization shows, close to 90% of cases had a fever and two-thirds had a dry cough.
The third most common symptom was fatigue. Almost 40% of cases suffered from it.
‘Sputum production’ was experienced by every third person. Sputum is not saliva. It is a thick mucus which is coughed up from the lungs.
Of the 55,924 cases fewer than 1-in-5 (18.6%) experienced shortness of breath (‘dyspnoea’). An earlier study, reported that a much higher share (55%) of cases suffered from dyspnoea, but this was based on a much smaller number of cases (835 patients).
Many of the most common symptoms are shared with those of the common flu or cold. So it is also good to know which common symptoms of the common flu or the common cold are not symptoms of COVID-19. COVID-19 infection seems to rarely cause a runny nose.
What can we do to prevent being infected?
The World Health Organazation has realeased a list of the steps we should follow to prevent us from getting coronavirus. Recommendations are: regular hand washing, covering mouth and nose when coughing and sneezing, thoroughly cooking meat and eggs and avoid close contact with anyone showing symptoms of respiratory illness (coughing or sneezing).
The growth rate of COVID-19 deaths
How long did it take for the number of confirmed deaths to double?
In the section below we present the latest data on the number of confirmed deaths by country.
But in an outbreak of an infectious disease it is important to not only study the number of deaths, but also the growth rate at which the number of deaths is increasing.
This is because even if the current numbers of deaths are small when compared with other diseases, a fast growth rate can lead to very large numbers rapidly.
To report the rate of change we focus on the question: How long did it take for the number of confirmed deaths to double?
Let’s take an example: if the number of confirmed deaths as of today is 1000, and there were only 500 deaths three days ago then we would say that it took three days for the number of confirmed deaths to double.
The doubling time of deaths has changed and it will change in the future. It would be wrong to extrapolate current growth into the future.
It is important to understand what it means for deaths to double. As long as deaths are doubling at a constant rate thegrowth is exponential. We humans tend to think in linear growth processes even when the growth is exponential, as psychological research has shown for decades. Below we give some intuition about exponential growth and provide the referenced psychological research on this.
Understanding exponential growth
It is helpful to remind ourselves of the nature of exponential growth.
If during an outbreak the number of deaths is in fact doubling and this doubling time stays constant, then the outbreak is spreading exponentially.
Under exponential growth 500 deaths grow to more than 1 million deaths after 11 doubling times. And after 10 more doubling times it would be 1 billion deaths.
This is in no way a prediction for the number of deaths we should expect; it is a reminder that exponential growth leads to very large numbers very quickly, even when starting from a low base.
It is important to be reminded of the nature of exponential growth because most of us do not grasp exponential growth intuitively. Psychologists find that humans tend to think in linear growth processes (1, 2, 3, 4) even when this is not appropriately describing the reality in front of our eyes. This bias – to “linearize exponential functions when assessing them intuitively” – is referred to as exponential growth bias.
Psychological research also shows that “neither special instructions about the nature of exponential growth nor daily experience with growth processes” improved the failure to grasp exponential growth processes.
Why is testing important?
Testing allows infected people to know that they are infected. This can help them receive the care they need; and it can help them take measures to reduce the probability of infecting others. People who don’t know they are infected might not stay at home and thereby risk infecting others.
Testing is also crucial for an appropriate response to the pandemic. It allows us to understand the spread of the disease and to take evidence-based measures to slow down the spread of the disease.
Unfortunately, the capacity for COVID-19 testing is still low in many countries around the world. For this reason we still do not have a good understanding of the spread of the pandemic.
How are COVID-19 tests done?
The most common diagnostic tests for COVID-19 are the so-called “PCR tests”. These tests rely on swabbed samples from a patient’s nose and throat.
The first PCR tests were developed within two weeks of the disease being identified, and are currently part of the protocol recommended by the WHO.
What do we recommend?
Our advice is to keep calm and follow the standard recommendations to stay healty. If you are not in an area where coronavirus is spreading, if you have not travelled from one of the areas or if you have not been in close contact with someone who has and is feeling unwell, your chances of getting it are low.
If you are in an area where there is an outbreak of the virus, you should follow the recommendations strictly, and take the matter seriously. Althought for most people with COVID-19 causes only mild illness, it can make some people very ill. More rareky, it can be mortal.