Covid-19 carriers 'most infectious earlier on'

People are most likely to pass on coronavirus within the first five days of having symptoms, an extensive study suggests.

The research indicates patients had the highest levels of virus early on in their illness and "live" virus, capable of replicating, was found up to nine days after symptoms began.

UK scientists say their study emphasises early isolation is critical to stopping spread.

The work appears in the Lancet Microbe.