With the onset of autumn , one phrase is on many people’s lips: persistent cough. But how many of us really know what it means, or what differentiates it from the barks and tickles caused by less dangerous autumnal illnesses?
A new and continuous cough is one of three symptoms of Covid-19 we are told to look out for. The others are a high temperature, and a loss or change of taste and smell. The NHS website defines a persistent cough as “coughing a lot for more than an hour, or three or more coughing episodes in 24 hours”.
“If a patient experiences any of these symptoms, we urge them to follow government guidelines, and self-isolate along with their household and get tested if at all possible,” said Prof Martin Marshall, the chair of the Royal College of GPs (RCGP).
Yet lots of autumn bugs can also trigger bouts of coughing, and shortages of tests may leave many of those with coughs wondering if it is really necessary to self-isolate.
“The terminology is a little bit confusing as it stands,” said Prof Jaclyn Smith, the chair of the British Thoracic Society cough advisory group, and a professor of respiratory medicine at the University of Manchester.
“I think what they mean is that it’s not just the odd cough that’s here one day and gone the next, but there’s a lot of coughing going on. We all have viruses where we get a runny nose and a sore throat, without coughing, but if it’s associated clearly with a cough, and you’ve got a decent amount of coughing going on, I think you do need to have Covid-19 test.”
Also, according to data from the Covid Symptoms Study app, if you have a cough related to a cold, it is unlikely to be so persistent that you cannot talk, keep you awake at night, or be associated with bad headaches and severe fatigue, as Covid-19 often seems to be.
“If you also have a runny nose, swollen glands and are sneezing, it is also highly unlikely to be Covid,” said Tim Spector, a professor of genetic epidemiology at King’s College London who runs the study. He added that coughing was less commonly seen in children with Covid, compared with adults.
The difficulty distinguishing between Covid- and non-Covid-related coughs is one reason why the RCGP is calling for major improvements to the test-and-trace system and for GPs to have access to Covid-19 tests to help differentiate between Covid-19 and other potentially serious conditions in high-risk patients.
Researchers at the University of Cambridge have also developed an app called Covid-19 Sounds, which they are using to collect recordings of people coughing, breathing and speaking, as well as asking about other symptoms, and the results of any Covid-19 tests. This data is being used to develop machine-learning algorithms, which could ultimately enable automatic detection of the condition.