Most people who have tested positive for COVID-19 have not had symptoms at the time that their samples are taken, according to a new study
Data from a recent study suggests that 77% of people had no symptoms on the day of their coronavirus test, while 86% did not have any of the main warning signs, such as a cough, a temperature or the symptom that seems to be defining COVID-19; a loss of taste or smell.
The results have led to warnings of COVID-19 “silent spreaders”, who are those who are asymptomatic of the coronavirus, from the scientists who worked on the study.
But some academics urged caution over the figures, saying that people who had recovered from their symptoms or may go on to have them and then tested positive would be counted as not having signs of the disease.
This comes after Boris Johnson is expected to bring in tough new COVID-19 restrictions next week for pubs within northern England, which could include shutting them down altogether in the cities of Liverpool, Manchester and Newcastle.
The symptoms research was led by Professor Irene Petersen at University College London and was based on information from the Office for National Statistics.
Prof Peterson has said that people may have had symptoms in the days previous to their test or developed them later on, but the figures have suggested that large numbers may be spreading the coronavirus while they are asymptomatic.
She said: “They may be silent transmitters and they don’t know about it. And so I think that’s a problem.
“You may have a lot of people who are out in the society and they’re not self-isolating because they didn’t know that they are positive.”
Professor Tim Spector of King’s College London, who leads the COVID Symptom Study (CSS) app, has warned that the research does not mean people will not have symptoms at all for the length of their infection.
He said that data from more than four million people who used the app and reported symptoms over a week found that 85% of adults reported having a fever, cough or a loss of taste or smell.
“But the data on children and the over-65s from the CSS app tell us a different story.”
“Only using the UK’s three classic symptoms will miss around 50% of cases in these important groups that were included in the ONS survey.”
“In a sub-study at King’s College London of twins using antibody testing and the ability to report 20 different symptoms, we showed that only 19% of people are truly asymptomatic.
“We need to learn from other countries and improve awareness of all the symptoms of COVID-19 to properly control the spread of the virus.”
This comes after Nottingham City Council has been urging people within the city to follow stricter guidelines as the number of COVID-19 cases at universities within the region continues to rise.
Professor Paul Hunter at the University of East Anglia has said that the UCL study could not show that the proportion of people with COVID-19 who went on to become symptomatic, or remained asymptomatic at some stage of their infection, as it only checked to see if they had external signs of infection when they actually took the coronavirus test.
He said: “Anyone who was previously symptomatic and had now recovered or who were currently incubating the infection and would develop symptoms within the following hours would not be included as being symptomatic in this study.”
A government spokesman has said that ministers are now aiming to increase the nation’s testing capacity to 500,000 a day by the end of October.