While Toronto will be moving to Stage 3 on Friday, the city's medical officer of health says COVID-19 is still present in the community, and residents need to stay focused to prevent a spike of new cases.

"We are making good progress in reducing the spread of COVID-19 in our city. As I have shared many times before, this is the result of your continued hard work," Dr. Eileen de Villa said during the city's coronavirus briefing.

She urged residents to keep following public health measures even with more businesses and places opening back up.

Toronto Public Health reported 19 new cases on Wednesday, bringing the total to 15,334. Of those cases, 1,153 have died while 13, 824 have recovered.

"We need to proceed with caution and care as we move forward. Whether it is dining indoors at a local restaurant, attending a concert, going to the movies or visiting a library, please keep washing your hands, watching your distance and wearing your mask," de Villa said.

"These measures are still needed to keep us as safe as possible as we move forward."

The city passed a roster of bylaws Wednesday afternoon to mitigate the potential spread of the virus as Toronto enters the next stage.

This includes making masks or face coverings mandatory in common areas in apartments and condominiums.

"As Canada's largest city, we need to consider what is necessary for our city and our local circumstances to move forward into Stage 3 and keep our residents and our city as safe as possible," de Villa said.

The doctor also joined CP24 to answer coronavirus-related questions from viewers.

CP24: What are your thoughts on Toronto moving to Stage 3 on Friday?

De Villa: I think this has been a long-awaited day for many of us here in Toronto. And it certainly is exciting and significant for us to move into stage three and start to get some of our city back. But as you've said, and as we've said many times over, COVID-19 is still here. I think we still need to be very careful and continue to practice all the public health measures that we've been advising people to follow -- watching your distance, wearing a mask and washing your hands. All the good things we've been telling people to follow to protect themselves and others around them.

CP24: Can you please explain to everyone again, what a bubble is? And how many can be in your bubble now, and then Friday?

De Villa: We are meant to keep physical distance from people as much as possible because this is actually what prevents the transmission of disease. This is what prevents the spread of COVID-19. We know the more we have people in close proximity with each other, in close contact and especially in indoor environments, it's easier for COVID-19 to spread. That being said, we know that people need to have contact with others.

Our provincial counterparts created this concept of a social circle so that you could actually have close contact. This is the group of people with whom you do not need to maintain physical distance. You can hug them. You can have close physical contact. That number has been 10 for the last several weeks, and it will continue to be ten even as we move into stage three on Friday.

CP24: What are the 50 and 100 numbers about?

De Villa: That is for gatherings of people, but still with physical distance. So, in an indoor environment, that number is now 50. Fifty people can be brought together in an indoor gathering but with physical distancing maintained. If we're talking about outdoor space, it's 100. That is what has been put forth by the province in their stage three reopening orders.

But again, physical distancing is still expected amongst those people unless you're talking about a group of people who are part of a social circle or bubble of 10. Those people may continue to interact with each other without having to maintain that physical distance.

CP24: Are you concerned about COVID-19 fatigue?

De Villa: How do we actually get and allow for people to have their lives back? These are important moments in life, weddings and those kinds of gatherings, which are significant occasions that we want to share with other people. How do we create that balance, so we allow people to have the opportunity to have people around them for these momentous occasions, while at the same time recognizing that we're trying to live with COVID-19 as safely as possible in our community? And that's the challenge.

It really does rest on each and every one of us. We still have to continue with our public health measures, watching that distance, washing your hands, wearing a mask when the distance can't be maintained and staying home when you're sick. It really does rest on each of us as we try to manage our new world with COVID-19 until we actually get treatments or vaccines. And we're hoping that people will be able to have that discipline and stick with public health measures. It's what has gotten us this far, and it's what will take us forward in the future.

CP24: With masks becoming mandatory in apartments and condos, shouldn't buildings be made to do a deep cleaning every day to minimize COVID-19 transmissions?

De Villa: Keeping places clean, and especially high touch surfaces are always important. It was given more significance earlier on in the COVID-19 pandemic because we didn't know a lot about how it transmitted. It's not that we know everything, but we certainly know more now. And while there is the possibility of spreading through those high touch surfaces and objects, we know that that's not as significant as the transmission of the disease that occurs when people are in close contact with each other, either breathing or talking in direct close contact with each other.

It doesn't really need to be super heavy-duty cleaning. It does need to be sufficient and good cleaning. We've put advice on our website for building operators and those who run apartment buildings and that kind of thing so that they know what good practice is when it comes to cleaning for those environments.

CP24: A viewer who works downtown in the financial district asks, are there any regulations that are going to come out for people that work in corporate buildings or offices, along with the stage three regulations?

De Villa: Most workplaces actually have Occupational Health and Safety advisors and are interested in ensuring that they keep their workforce healthy. I know that a number of workplaces downtown where remote work is possible, they're facilitating continued remote work or at least part-time work from home and work from the office in other days so as to try to balance the load, so there aren't so many people in one place at a time. But certainly, the mainstays continue to be physical distancing, staying home when you're sick, washing your hands and when you can't maintain physical distancing wearing a mask. This will apply in every setting, whether we're talking about out and about in the community or the workplace.

CP24: Given the bylaws to use masks in all public indoor settings, which is getting expanded today to include bars, restaurants and condos, apartments, how is that different from public schools? Kids and school staff will come from different social circles currently limited to 10. And a large number of TDSB schools are populated more than 50 people indoors per stage three directives.

De Villa: We've increasingly learned over the course of this pandemic that masks are quite helpful in reducing the potential for somebody to spread COVID-19, whether it's knowing or unknowing people who have no symptoms. Wearing a mask prevents the spread of potential disease from one person to the next. There is less benefit from a cloth mask or a non-medical mask to protect oneself, but the major benefit is preventing the spread of disease from you to somebody else. And to the extent that we all wear them, we're all protecting each other.

We are beginning to understand a little more about how transmission changes and how they are different in different age groups. And there is some evidence to suggest that kids perhaps may not transmit COVID-19, as well as older children or adults. But this is still very much an evolving science. From a public health perspective, we're saying that as much as people can wear masks of all ages, above a certain age so that you're developmentally able to manage to wear the mask and to take on and put on the mask yourself, and assuming that there aren't any other reasons why you shouldn't wear a mask, we're recommending you should wear a mask, especially when you're in an indoor environment where physical distancing might be difficult to maintain. That would apply to kids as well.

I appreciate that school boards and schools have their purview, and they get to make their decisions under the provincial regime. However, to the extent that people can wear masks in school environments, that will help protect everybody to the maximum extent possible.

CP24: Do you find that the science community is getting more of a handle on this virus? Do you see great strides and understandings, or are there still such huge question marks?

De Villa: I would say it's both. I'm not sure that it's an either-or. There are still question marks. There are still unanswered questions. But since the beginning of the pandemic earlier this year, we've learned a phenomenal amount more about this virus. We certainly are further ahead. But there is still much more that we need to know.

CP24: What's the one thing that stands out for you right now that we didn't know about COVID-19 initially?

De Villa: Our understanding has evolved. We weren't sure about whether there was anything such as pre-symptomatic or asymptomatic transmission. We now have increasing evidence that there is a pre-symptomatic transmission, and there is an asymptomatic transmission of COVID-19. And the other question that we just spoke about earlier around how much is spread through surfaces and touching surfaces that are contaminated versus what spread person to person? We know more now that you know person to person spread is more significant. I don't think we can say exactly how much, but we certainly know it's more significant person to person spread than spread of disease through touching surfaces.

CP24: What are the rules now for passengers in my car?

De Villa: What should be happening is that you're going to want to be in that in a car with people who are in your bubble. That's what's optimal because it's a closed environment. And we know that there have been occasions where COVID-19 has been passed from one person to the next in a vehicle. It's a closed space, especially if the windows are closed, and if it is quite a lengthy commute or trip. A significant amount of time in a closed environment in close contact makes you hit all the points on COVID-19 transmission. If you have to be in that circumstance with people outside of your social circle, one, you're going to want to keep that time as short as possible and two, I would strongly recommend wearing a mask and wearing as much as possible. I would open the windows to try to keep the air flowing because ventilation will certainly help reduce the likelihood of COVID-19 spread from one person to the next.

CP24: Is it safe for you to eat together at a restaurant with people who are not within your bubble?

De Villa: It is technically possible. But again, you're not really meant to have close contact with people outside of your bubble. If you are to do that, I think that the way to try to minimize risk is still physical distancing. That's the core of preventing the spread of transmission. You can further reduce the risk, especially while the nice weather is here, by eating in the outdoor space. You would still want to maintain that physical distance as much as possible, but at least you're reducing your risk significantly by being in outdoor air where the likelihood of transmitting COVID-19 from one person to the next is definitely reduced.

CP24: If I wear my three-layer non-disposable cotton mask for, say five to 10-minute intervals, how many times can I wear it before having to wash the mask?

De Villa: The general advice is to one make sure you're using that mask correctly. Don't forget to wash your hands. Only touch the loop part rather than the mask part of the mask. And yes, you can use your mask for the day. The best thing to do is to wash it at the end of the day. If possible, if you can keep a few masks on hand so that you can have one in the wash and one ready to go, and another one a backup is fair. That's probably the best thing possible. But the important part is to use the mask properly. Try to wash it at the end of the day. Thanks for protecting the people around you.

CP24: How comfortable do you feel going indoors once we're into stage three into your favourite restaurant?

De Villa: Outdoors is always best. And you know what, why not enjoy the summer weather while it's here. It's all too short for us. When you can, enjoy the outdoors.

This interview has been edited.