More than half of patients with Covid-19 have been infected by persons who showed no symptoms.


More than half of people infected with coronavirus were infected by someone who was showing no symptoms, a study has found.

Academics in Ireland reviewed 17 global studies to estimate how much coronavirus can be spread during the "presymptomatic" period.

They found between 33 and 80 percent of cases to be infected by people who had no idea they had been infected.

It takes an average of six days before a person develops signs of coronavirus, which includes persistent fever and cough.
More than half of patients with Covid-19 have been infected by persons who showed no symptoms.

More than half of people infected with coronavirus were infected by someone who was showing no symptoms, a study has found.

Academics in Ireland reviewed 17 global studies to estimate how much coronavirus can be spread during the "presymptomatic" period.

They found between 33 and 80 percent of cases to be infected by people who had no idea they had been infected.

It takes an average of six days before a person develops signs of coronavirus, which includes persistent fever and cough.


But in those days before the symptoms, patients are contagious and can pass the deadly virus to others.

The transmission is most likely to be infected the day before symptoms begin, the team concluded.

Pre-symptomatic spread control is essential for keeping the disease at bay when restrictive measures are eased, experts said.

This depends on the success of the contact tracking, which involves identifying all individuals who have been in close contact with a confirmed case.