Chinese authorities began publishing daily figures on April 1 on the number of new cases of asymptomatic coronaviruses.
New research suggests that about four in five new Covid 19 infections have caused no illness in those who contract it, reports the main medical publication of the British Medical Journal.
Experts believe that unnoticed aysmptomic cases of the virus could be an important source of how it contracts and spreads in the population.
The National Health Commission of China said that 130 of 166 new infections – 78% – identified within 24 hours of April 1, showed no symptoms.
The data also revealed that most of the 36 cases in which patients had symptoms involved overseas arrivals, compared to 48 the day before, reports the BMJ.
China – where the epidemic began – is rigorously testing foreign arrivals for fear of importing a new covid-19 epidemic.
Tom Jefferson, epidemiologist and honorary researcher at the Center for Evidence-Based Medicine at the University of Oxford, said the results were “very, very important.”
He said BMJ: “The sample is small and more data will be available. Furthermore, it is unclear how these cases were identified.
“But let’s just say they are generalizable.
“And even if they are eliminated at 10%, it suggests that the virus is everywhere. If – and I insist, if – the results are representative, then we must ask ourselves: “What the hell are we going to lock ourselves up for?” “
Jefferson told BMJ it was “very likely” that the coronavirus had been circulating longer than expected and that a large number of the population had already been exposed to it.
The results raised concerns that people with no symptoms could spread the virus without knowing it.
Currently, China has seen a decline in the number of infections and deaths and has eased some locking restrictions from previous epidemic hotspots.
But senior Chinese government medical advisers say the asymptomatic infections could not cause another major epidemic of covid-19 if these people were kept isolated, normally for 14 days.
Once asymptomatic infected people are identified, they and their contacts would be isolated and kept under observation.
Citing classified data, South China Morning Post said China has already found more than 43,000 cases of asymptomatic infection through contact tracing.
The latest findings appear to contradict a report by the World Health Organization in February that was based on Covid-19 in China.
The report findings suggest that “the proportion of genuinely asymptomatic infections is unclear but appears to be relatively rare and does not appear to be a major driver of transmission.”
But since the WHO report, other researchers, including Sergio Romagnani, professor of clinical immunology at the University of Florence, said they have evidence that most people infected with the virus have no symptoms.
Romagnani led research that showed that coverage tests in a completely isolated village of around 3,000 people in northern Italy saw the number of people with Covid-19 symptoms drop by more than 90% in 10 days isolating symptomatic people and those who were asymptomatic.
In an article on the Center for Evidence-Based Medicine website, Jefferson and Carl Heneghan, director of the center and editor of BMJ EBM, write: “There is no doubt that covid-19 can be much more widely distributed than some people think.”
“The lockdown is going to bankrupt all of us and our descendants and it is unlikely at this point to slow or stop the viral circulation while the genie is out of the bottle.”
“The current situation comes down to this: is economic collapse a price to pay for stopping or delaying what is already among us? “
The UK is currently in its second week of foreclosure to stop the spread of the virus and reduce the number of deaths.
Currently there are 41,903 confirmed cases of Covid-19 in the UK and there have been 4,313 deaths.