Masks are returning across Australia as COVID cases soar and yet another wave of the virus prompts authorities to appeal for public help in stemming infections.

Cases in the nation’s two most populous states have more than doubled in the space of two weeks, although the number of serious infections remains low.

NSW and Victoria reported 48,267 new infections on Friday, up from 36,436 the previous week and 22,676 two weeks ago.

Health authorities in NSW have asked people to resume wearing masks in public indoor areas and on public transport, although they have stopped short of reintroducing mandates.

Masks will, however, be mandatory in hospitals and similar settings.

“Implementing these changes now means that our staff and the community can look forward to the festive season with greater confidence,” NSW Health deputy secretary Deb Willcox said on Friday.

“Family and loved ones can still spend time with patients however, we do ask people to please limit the number of visitors coming to see patients at any one time.

“Visitors as well as staff will now also need to wear a mask in all areas of a hospital or health service, not just in the patient areas, as was previously the requirement.”

Victoria’s health authorities issued a similar recommendation for masks, as well as booster vaccinations for those eligible.

“COVID-19 hospitalisation and case numbers have increased for a fifth consecutive week in Victoria,” chief health officer Brett Sutton said in his weekly update.

“It is expected these rates will continue to increase for several weeks and likely peak around early December.”

Professor Sutton said the growth in cases and hospitalisations in Victoria is being driven by multiple emerging Omicron subvariants, including BQ.1.1.

A new BA.2.75/BA.5 recombinant, XBF, had also been identified in Victoria. It accounts for more than 10 per cent of sequenced cases.

“Indications from Singapore and western Europe suggest this wave may pass relatively quickly, although differing local conditions may have an impact,” Professor Sutton said.

Last week, Queensland health authorities confirmed the state’s fourth wave was well underway – and likely to peak in early December.

Queenslanders were also advised to wear masks in high-risk situations, and ensure they were up to date with vaccinations.

South Australia’s chief medical officer, Nicola Spurrier, said the situation was similar in her state, and masks were now encouraged. But she dismissed the idea of tighter restrictions.

“As you can see it’s not necessary,” she said earlier this week.

“We have to get used to the fact that this is going to continue to come in waves.

Despite the rising case numbers, there were only 45 people in intensive care with the virus across NSW and Victoria on Thursday.

The figures represent a fraction of those during the peak of the previous COVID wave in July.

Earlier in the week, federal Health Minister Mark Butler said the government’s vaccine advisory body didn’t recommend the rollout of a fifth vaccine dose, or third booster, despite the rising caseload.

He said the group noted an extra booster was unlikely to reduce the fourth wave of cases.

Elsewhere, Carnival Cruises has made mask-wearing compulsory again on its ships after a spate of cases onboard.

Management said the health measure would return out of an abundance of caution due to the evolving public health situation.

The measure was scrapped for passengers in February and for staff last month.

Meanwhile, a study on the impact of the first NSW COVID-19 lockdown on almost 900 kids and carers in out-of-home care found restrictions had a great effect on young people’s education, behaviour and social and physical activities, as well as time spent with birth families.

It had a huge bearing on carers’ financial situations as well as their access to services and support.

However, research published by the University of Wollongong, University of Canterbury and University of NSW shows some families still had a positive experience.

Twice as many children reported a positive experience than negative one, which the authors said backed up other studies suggesting the first lockdown allowed children with complex needs to access greater emotional support and a sense of security.

“It may also be that the restrictions provided some children with an opportunity to develop stronger relational ties with their carers,” they noted.

Weekly virus data by jurisdiction

NSW: 27,869 cases, 39 deaths

Victoria: 20,398 cases, 46 deaths

Northern Territory: 286 cases, no deaths

– AAP