Surprising research findings on the early symptoms of COVID-19

September 23, 2020

This article has not been updated recently

We have been busy researching what the early symptoms of COVID-19 really are, as this information is essential to helping us all stop the spread of the virus in the coming months. If we can spot cases based on symptoms sooner, people will be able to start self isolating in those first few days and stop the accidental spread of the virus.

So what have we found out about the early symptoms (first seven days) of COVID-19 - when people are at their most infectious?

Headache and Fatigue - the Dark Horses of COVID Symptoms

Our data shows that the most commonly experienced early symptoms are actually headache (82%) and fatigue (72%) - and this is the case for all age groups. Only 9% of COVID-positive adults aged 18 - 65 didn’t experience headache or fatigue. Of course, headache and fatigue commonly occur in other conditions which is why they don’t trigger a test on their own.

In fact, only 1% of people who reported fatigue and/or headache on our app ended up testing positive for COVID. So while headache and fatigue are commonly found in people who have COVID (alongside other symptoms), having either or both of those symptoms alone is unlikely to be indicative of COVID.

The Classic Three are Still Key

40% of all age groups reported having a fever in the first seven days, and this or loss of smell and persistent cough are still the key symptoms to be aware of - so people with the classic three symptoms of persistent cough, fever or loss of smell should certainly seek a COVID test.

Age Isn’t Just a Number

We saw some key differences in early COVID symptoms between adults, children and the elderly. The symptoms of headache, loss of smell, persistent cough and sore throat are more often reported by adults (18-65) than by the elderly or children. The adult age group tends to report more loss of smell (55%) than the elderly or the kids (65+ yrs: 26%, <18 yrs: 21%.). This doesn’t mean loss of smell is not important in older people or kids, but probably means we need to actually test for smell changes, especially if reporting for someone else.   

Those over 65 reported being confused, disorientated and having severe shortness of breath more often than the other groups, while overall these symptoms are less common in those aged 18-65.

To highlight the differences between the three groups, this infographic shows the top symptoms in the first 7 days by age groups (ordered by most to least frequent):

So how did we come to find these differences?

We used data from app users who tested positive for COVID-19 from a PCR (swab) test. All statistics correspond to the symptoms reported by these individuals in the first seven days after onset. In the dataset, we considered individuals with onset of symptoms from 2 weeks before the test up to 1 week after the test, and only considered symptoms that appeared up to sevens days after the onset. All users had to report feeling healthy in the period preceding this, before beginning to report feeling unwell. 

To help visualise these findings we describe above, we have created an infographic here  go check it out and feel free to share any interesting nuggets of information you find there with your friends and family so they are in the know too!

We will continue to release new findings so keep your eye peeled for more updates on this topic. 

We hope you found this blog informative and useful. Please bear in mind that we are providing percentages and averages and in medicine there may be rare exceptions. As always, a big thank you to all of you who continue to contribute to the COVID Symptom Study - it’s thanks to you that we can carry out this important research. 

Keep logging, keep safe! 

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