The woman was reportedly carrying a knife when staff at the home in southern New South Wales called the police.

An ageing population coupled with the incidence of high-risk diseases and their children's return to a normal life at the office may mean a greater demand for such services.

Only about a fifth of old folks' homes and centres for disabled people have responded so far.

The outbreak was traced to an unvaccinated worker with a Covid-19 variant, the study by the US Centers for Disease Control and Prevention says.