The virus that causes COVID-19 is evolving, with new and more infectious variants taking hold.
Most mutations are harmless, but occasionally the virus acquires genetic changes that give it an advantage
Mutations in the spike protein on the surface of the virus can make it easier for it to attach and enter human cells
The more the virus spreads, the greater the chance a dangerous mutation will occur
Last week, Victoria entered a seven-day lockdown due to another COVID-19 outbreak.
That has now been extended for at least another seven days in Melbourne.
But what makes this outbreak different from others is the spread of a “highly infectious” variant that was first detected in India in October last year.
There are currently four coronavirus variants of global concern that have been identified by the World Health Organization (WHO), each first detected in India, Brazil, South Africa and the UK.
Authorities in Vietnam have also identified a “dangerous” new hybrid variant that is a mix of the types first detected in the UK and India.