TORONTO -- After federal COVID-19 modelling showed that the fall could bring about yet another surge in COVID-19 cases with the Delta variant spreading rapidly, doctors say that the best way to avoid a fourth wave is to vaccinate, test, trace and isolate.

Canada鈥檚 Chief Public Health Officer, Dr. Theresa Tam, released modelling on Friday that indicates cases are beginning to rise as a result of the more contagious Delta variant, but there is still time to flatten the curve.

鈥淭here's no summer vacation for getting second doses and first doses, because we don't have that leeway,鈥 Dr. Lisa Barrett told 愛污传媒 Channel on Saturday.

She added that people who are delayed in getting their shots, first or second, need to make an effort to get it as soon as possible.

鈥淏efore we get into all of these back to school and other situations in a respiratory virus season like the fall, we鈥檝e got to keep going,鈥 she said.

While breakthrough cases have happened among vaccinated people, they remain rare and vaccines remain the best defense against COVID-19.

鈥滻t very much is that these vaccines are amazing, and the cornerstone of our prevention toolbox, and our control,鈥 said Barrett. 鈥淭he limiting of virus really, really depends on people getting two doses of this vaccine.鈥

There are other steps Canadians can take to continue protecting themselves, vaccinated or not, and they鈥檙e no different than what鈥檚 been urged since early on in the pandemic: masking and testing.

鈥淭here's some simple tools out there, in addition to vaccines, like masking and testing, that would reduce the risk of this being a disease of the unvaccinated,鈥 Barrett said.

While the modelling shows the potential for a fourth wave in the fall, an infectious disease specialist said that models are only as good as the variables put into them, but that the possibility of another surge is possible.

鈥淚t's possible that we could have a sort of fourth wave. I would guess that it could be a muted fourth wave, because unlike previous waves, we do have vaccinated people,鈥 Dr. Ronald St. John, former director-general of the Centre for Emergency Preparedness and Response, told 愛污传媒 Channel on Saturday.

While provinces begin to loosen restrictions, or in some cases do away with them altogether, one doctor says that it鈥檚 the unvaccinated population who will be hit hardest by a fourth wave.

鈥淭he fourth wave is certainly going to affect those who are unvaccinated, but I think what we really need to start looking at are, who are these unvaccinated populations?鈥 Dr. Veronica McKinney, director of Northern Medical Services at the University of Saskatchewan, told 愛污传媒 Channel on Saturday.

She said that unvaccinated populations need to be identified in order for doctors and experts to work with them, so that they can be comfortable getting vaccinated to protect themselves and others.

鈥淭he way that it's been portrayed is that it's an individual choice and that people are just being resistant but I really believe that now is the time to look at what are the pieces that have led to this in the system?鈥 she said.

Policies need to change to encourage people to get vaccinated, but also to take time off in the event they do get sick, added McKinney.

鈥淲e need to look at those policies that are making it difficult, those people who don't get sick time, who don't want to be tested because they don't want to be off work but also not necessarily trusting what is being presented,鈥 she added.

Even with getting more shots in arms, McKinney said that provinces such as Saskatchewan and Alberta have lifted public health measures necessary to test, trace and isolate in a way to prevent a fourth wave.

鈥淧art of the challenges that our communities are now dealing with is the fact that there are no longer public health orders that we can use to try to help in terms of keeping people isolated if they need be, testing, all of those pieces that were very helpful, but are no longer existent [Saskatchewan]," she said.