A second resident at a Melbourne aged-care facility has tested positive for COVID-19, despite being fully vaccinated.
The Arcare Maidstone facility was locked down over the weekend when a staff member tested positive for the virus. Since then, three other people from the home have also contracted COVID-19.
On Wednesday, the latest case, an 89-year-old man, was transferred from the facility to hospital.
Arcare chief executive Colin Singh confirmed the man had received both doses of the vaccine and said the facility is "deeply saddened" by the latest case.
Although vaccination reduces the chances of infection by around 95 percent, it is possible to catch the virus despite being fully vaccinated.
In California and Texas, only 0.05 percent of fully vaccinated healthcare workers tested positive for COVID-19.
The Centre for Disease Control says while experts are still researching how common these cases are, it's possible those who contract the virus after vaccination may experience less severe symptoms.
"The overall risk of hospitalisation and death among fully vaccinated people will be much lower than among people with similar risk factors who are not vaccinated," it says.
A third of Arcare Maidstone's 110 staff and 53 of 76 residents had received at least their first dose as of Sunday.
Victoria's outbreak now stands at 63 cases, with three new locally acquired infections recorded on Thursday.