What is the Delta variant of COVID-19 that has been detected in both Sydney and Melbourne?
The highly infectious Delta variant has been detected in Sydney's coronavirus outbreak. It is the same variant that was detected in Melbourne's latest outbreak, however, the sources for the infections are different. Here's what you need to know about the Delta variant. The Delta variant is a highly contagious variant of COVID-19. Health authorities are particularly concerned by it because it appears to be:  More infectious than other variants  More infectious than other variants More resistant to health controls and preventions such as isolation  More resistant to health controls and preventions such as isolation Causing more varied and severe symptoms among patients  Causing more varied and severe symptoms among patients Spreading more easily among children  The Delta variant is also known as B.1.617.2 and was previously known as the Indian variant. The Delta variant was first detected in India in October last year. It is currently the dominant strain in the United Kingdom, according to Public Health England figures. UK authorities have estimated the Delta variant is 40 per cent more infectious than the Alpha variant that sent Britain into lockdown at the start of the year. NSW Chief Health Officer Kerry Chant confirmed on Thursday that the Sydney driver who tested positive for COVID-19 had the Delta variant. Dr Chant said tests showed the driver's variant matched "perfectly" with a sequence from the United States. The driver is a man in his 60s who drives a limousine as part of his work and is involved in transporting international flight crews. While the recent COVID-19 outbreak in Victoria also involved the Delta variant, that outbreak was linked to a different source of infection. Victorian Chief Health Officer Brett Sutton confirmed in early June that the Delta variant had been identified in a coronavirus case. Genomic sequencing showed a link between a returned traveller who entered Victoria from Sri Lanka in May and a family in the West Melbourne cluster. Anyone with symptoms of COVID-19 should get a COVID-19 test, even if the symptoms are mild. Further testing is required to determine which type of variant a person has once they have tested positive to COVID-19. Symptoms usually appear five to six days after a person has been infected with COVID-19, however symptoms may appear between two and 14 days after exposure. Government scientists in India have published a report saying the Delta variant can be caught by people who have already had the disease or been only partially vaccinated. More studies are underway, but there is some promising evidence from the UK that the AstraZeneca and Pfizer vaccines provide a similar level of protection against the Delta variant as they do against the Alpha variant. A study published on May 22 showed two AstraZeneca doses were 60 per cent effective against the Delta variant, while Pfizer provided 88 per cent effectiveness.