As COVID cases in Ontario slowly climb once more and vaccination levels plateau, health experts are warning that the pandemic's fourth wave could potentially get serious, leading residents to wonder if some stricter iteration of lockdown will return in the fall.

Though we haven't yet moved past Step 3 of reopening despite the requisite 21 days elapsing, Doug Ford has assured the public there won't be more business closures.

But, some restrictions will remain in place even after we graduate out of Step 3, including, we learned last month, face coverings in indoor public places.

Seeing as the province's chief medical officer of health has referred to post-Step 3 as "a full opening with some public health measures, if appropriate," it shouldn't be much of a surprise that some new norms of pandemic life will continue.

And, Public Health Ontario has revealed further details of what these will be and how long we can expect them to stick around for.

In a report about considerations for fall and winter COVID-19 planning, PHO stated that measures such as  contact tracing, masking, hand hygiene, and other infection protection measures, especially in indoor public places, "remain important in the control of Delta."

The document cited studies from other parts of the world that show how crucial it is to retain at least some basic measures moving forward into the coming months, noting that, based on research, "estimating herd immunity may not be attainable even in the context of high vaccination rates" given variants of concern.

This will, it says, mean that simple public health habits like the above plus case isolation, home quarantine, school closures and social distancing, will be necessary through fall and winter 2021-2022, which hold a high amount of uncertainty at this point.

Mitigating transmission and stress on the healthcare system remain of key concern leading into cold and flu season, PHO says, adding that the future as far as key public health indicators are concerned will be dependent upon unpredictable factors like how citizens will behave and if and when vaccines will be approved for younger children.

"Vaccination coverage is increasing across Ontario and vaccination targets previously set to progress through a 3-step reopening plan have been met, with the transition to 'full reopening' remaining. From the public health perspective; however, the emergence and spread of SARS-CoV-2 VOC Delta has changed pre-existing assumptions about the prevention and control of COVID-19," the report reads.

"Maintenance of less restrictive public health measures may be useful for prevention, and may have corollary benefits against expected non-COVID-19 respiratory virus circulation in the fall. Scenarios, risk reduction and mitigation strategies are important for fall 2021 in order to maintain and improve upon control of the SARS-CoV-2 pandemic so that Ontario can enter into a sustainable recovery period for all of society."