From today, people who test positive for Covid will only need to quarantine for five days - after negative tests on day five and at the start of day six.
The Omicron variant brought problems for employers, who've struggled to operate with staff off isolating.
Merton’s Director of Public Health, Dr Dagmar Zeuner, says studies show that people spend different amounts of time being a threat to others.
She says that many people will no longer be infectious after five days, but you have to be absolutely sure.