South Africa’s Health Minister Dr Zweli Mkhize says new research estimates 12 million people - about 20% of the country’s population - could already have been infected with coronavirus.

This is much higher than the official cumulative number of detected Covid-19 cases which is 650,749.
The research is based on examining seroprevalence - the amount of antibodies present in a patient’s bloodstream.

In a statement released on Monday night, Dr Mkhize said a decline in cases has raised questions of what level of immunity might exist in the country.
He explained initial samples had shown "seroprevalence of between 29 and 40%".

A national seroprevalence study is now underway.
The results of a similar study in England published in August found that 6% of people had antibodies to coronavirus. The prevalence was highest in London, where the number rose to 13%.

It is unclear how long immunity to coronavirus lasts, or whether being exposed to the virus means an individual is protected from being infected a second time.