Toronto's top doctor says she is concerned about the rise of COVID-19 infections in the younger population.

"We are now seeing more 20 to 39-year-olds getting COVID-19 compared to earlier in our outbreak," Dr. Eileen de Villa said during the city's COVID-19 briefing.

"I am very concerned about this given recent trends amongst this age group in other jurisdictions.

Despite the continuing decline of cases in Toronto, de Villa said new infections are still being reported every day. Over the past two days, Toronto Public Health recorded 58 new coronavirus cases.

The doctor said the city has plateaued its COVID-19 cases with its seven-day moving average of new infections remaining consistently in the high 30s and low 40s.

De Villa noted that she is also concerned about people who believe that the pandemic is over.

"I'm here today to tell you that this is simply not true. My message to you is that we must remain vigilant," de Villa said.

The doctor also answered questions related to COVID-19 from viewers.

CP24: There have been reports in the media in the United States about masks and carbon dioxide. We wear masks to protect everyone from COVID-19. However, are we breathing in the carbon dioxide we're supposed to expel when we use masks? Is this a real thing?

De Villa: I've told a couple of people about masks, and I know that this is a concern. These masks are not meant to be super tight fitting. We're not talking about N95 masks here when we're talking about the general public. We're talking about cloth masks. Lots of space, lots of room for oxygen to get through to the sides, through the gaps that exist, and they're not supposed to be big gaps. We're talking about tiny molecules here. They can get through the mask as well. I will remind people that in health-care settings, health-care professionals have to wear masks for hours on end. Sometimes some surgical procedures last for a really long time, and they're wearing masks for hours. We want their oxygen levels to be good so that they can continue to do their important work. I don't think that this is something that people need to be concerned about. I recognize that that information is out there on the Internet, but this is not a concern from my perspective at all. Oxygen will get through. This is in the case that you don't have a medical condition or breathing condition that is involved in the situation.

CP24: I've noticed that some people are wearing their masks below their nostrils, but covering their mouth. Is this an effective way to use a mask? Would you please comment on using a face shield instead of a face mask?

De Villa: Wearing the mask below your nose, that's not good. That's not going to work. When we're talking about COVID-19 transmission, we're talking about droplets and secretions that come out of your nose and mouth. You must wear your mask properly in order to protect the people around us. And that's done by actually having the mask cover your nose and your mouth.

Face shields I know are easier to use. It's easier to breathe, and yes, they offer some protection for your eyes. But they are not a substitute for masks. Masks are the best when it comes to protecting others from the potential that we might be spreading COVID-19 to them. That's how we best protect each other. Remember, I wear my mask to protect you. You wear your mask to protect me, but in order for it to have that protective effect, it actually has to be covering your nose and your mouth.

CP24: Why can we not see our doctors? I know that COVID-19 takes priority, but not being able to see your specialist or your family doctor for six months is a little much. Virtual visits are a waste of time. My wife has a rare condition which needs to be monitored frequently. When are we able to actually see our doctors?

De Villa: This is starting to come back and return we're seeing services resume and hospitals and yes, within clinical settings as well. Depending on what kind of care is needed and what the unique circumstances of the patient are, my suggestion is to call discuss that with your physician and come up with a plan. I think there is much that's starting to resume, particularly in clinical care. We knew we needed to be careful around COVID-19, but there are other medical conditions that need to be managed. Those should be discussed between individual patients and their physicians so that everybody is as safe as possible.

CP24/video question: I'm a single parent of two young children, and I want to tell you what happened to me because I want to ask your opinion. I had to go to Sick Kids emergency to get a COVID test for my baby. I was told I could not bring my four-year-old with me that only that one parent could go and no siblings because they were afraid of the health risk. But I had nowhere to leave my four-year-old because I couldn't leave him with my 77-year-old immunocompromised mother if we did have COVID. Is this the protocol in Toronto hospitals?

De Villa: There's no question that there have been a number of challenges through COVID-19. People have been finding themselves in these circumstances where they need to take care of themselves or take care of other family members, but they have no access to child-care. This is, for sure, a challenge. I don't know the specifics around what the policies are at the Hospital for Sick Children. Each hospital has its infection prevention and control policies. And of course, they're meant to follow some general rules and principles to minimize the likelihood of COVID-19 transmission. But I think, as with every rule, there are always opportunities for exceptions. I don't know whether that might be something that could have been discussed with the hospital at the time. My suggestion would be that the good people at the Hospital for Sick Children are interested in doing the best not only for the community but for individual patients. I think it's worth a conversation with them to see what they would suggest and to see what they might be able to do to prevent the same kind of anxiety happening to somebody else in the future.

CP24: It was based on recommendations from British Columbia's Ministry of Health regarding protecting yourself from COVID-19 during sex effectively with people outside of your bubble. While I'm not going to name the act here, you know, I wonder if Toronto Public Health has any recommendations about sex during COVID-19?

De Villa: Well, I think our recommendations wouldn't be all that dissimilar from what our colleagues out in B.C. would suggest. It's always a question of trying to balance risk with benefit. We're humans, and we have a need for closeness and physical contact with others. How do you do that in a world where we're trying to live as safely as possible with COVID-19? I think practices that can be used to gain physical contact and get closeness and have some intimacy with others while at the same time trying to minimize the risk of transmission of COVID-19 are perfectly reasonable things to do, particularly if you're looking to expand your bubble. I think these are very practical and reasonable things. I think that what we would provide, by way of advice, would be very similar across all the different public health agencies.

CP24: A viewer says her daughter just had a baby and she's very concerned about COVID. Is it safe for them to meet the new baby if they wash their hands and wear a mask?

De Villa: It's all a question of trying to maintain that bubble and understanding how we minimize the risk here. Washing hands and making sure that you're staying within your social bubble, are probably the best things that are out there in terms of protecting risks to those of us in our in our social circles.

It's interesting. I haven't seen that much literature with respect to newborns and COVID-19 risk. It does exist. But we know that when we look at who has been most affected and has had the most severe outcomes associated with COVID-19, it's actually in the older age demographic. Those men above the age of 60 have been most impacted when I look at our data in Toronto. These are the kinds of things that we're paying attention to. Those are good reasons for us to continue to do good practices -- wearing a mask, maintaining physical distance and of course, and washing your hands.

CP24: A viewer wants to know about contact protocols. I'm day 10 in self-quarantine after returning from the U.S. and just got an email regarding this. I have four days left and no one called as we were told they would, how often is this happening?

De Villa: When it comes to that particular follow up a quarantine for international travellers and following up on that is actually under federal purview. Managing the quarantine act and management of international travellers is something that falls to federal public health authorities. That's a question that's really more properly directed towards them.

But at the end of the day, protecting our community against COVID-19 and making sure that we're doing the best to protect each other is the responsibility of each and every one of us. If travellers are aware, as they've returned from international travel, that they should be isolating appropriately at home, then we should expect that as part of our jobs, and part of our responsibility to our community, is to follow that advice. Isolate appropriately. It's 14 days, which in the grand scheme of things is not that much, especially if it's something that we do to protect each other and to protect our community.

CP24: Aren't you worried as a public health official that people returning from international travel that perhaps Health Canada or whoever is responsible for making these follow-up calls may not be properly doing it as expected? If you're in isolation, you're quarantining yourself, and you're expecting that phone to ring it, it doesn't. Some people are concerned, and some people may just ignore it.

De Villa: It would be better to have that follow up, especially if you were told that you should expect that follow up. That being said, at the end of the day, it still does come down to each and every one of us because even if they follow up if you don't follow the advice, it doesn't matter whether they make the call or not. We're trying to take care of each other, and we've done a really good job. I have seen a great deal of cooperation, a high level of collaboration, certainly amongst Torontonians. We would encourage people to follow the good advice because, at the end of the day, it does come down to each and every one of us adhering to the best advice in order to protect our community.

CP24: A viewer says we received an email from the TDSB, saying students will not have to wear masks when they return in September. I thought they're mandatory inside public spaces. Are schools exempt?

De Villa: What we've got is a masking policy in indoor public spaces. When you think about public spaces, we're talking about spaces where members of the general public can readily go in and out of. Schools don't generally fit that bill. Doors are usually close at certain points in the day in order to ensure that they're providing a safe environment for our students. I think there's a lot of conversation. I know there's a lot of ongoing conversation, whether it's at the Ministry of Education, whether it's with the Ministry of Health and at the individual school boards, to try to understand what might create the best circumstances for kids to return to school safely. Mask use may be part of that conversation, and how it will actually play out, I think, still remains to be seen. We appreciate how important schools are to kids, how important they are to our parents, and their ability to get back to work. It's a major investment, and it requires careful thought, careful consideration.

CP24: Would you feel safer if kids were masked in schools, especially the older ones?

De Villa: Well, I think that what we're seeing in the science is that particularly with the older kids, they're showing the same ability for spreading COVID-19 as adults do. With older kids, if we can get them to wear masks, it's just one more layer of protection. One added practice that we could do to try to make schools as safe as possible, so we get the benefits while minimizing the risk of COVID-19.

CP24: Will any protocols change on the golf course, once we reach stage three? For example, will the rakes be allowed in bunkers? Will the holes return to normal depth?

De Villa: Those are some tough questions. I have to be honest with you, I'm not sure that I know the specific answers to those. There are precautions that are in place to minimize the risk of COVID-19 to the extent that they don't completely distract or take away from the enjoyment of the golf game. Why not practice things that actually reduce your risk of either acquiring COVID-19 or potentially transmitting it unknowingly to somebody else. Those all strike me as very reasonable things to do in the interest of best protecting the health and our community. I admit I'm going to have to go and look those up and see if I can get back to you on those specific questions. But why not take precautions if you're still able to enjoy your game and use precautions to minimize risk? Why not continue to do those things?

CP24: As of today, there's now four weeks of data of Toronto in stage 2 of the COVID reopening protocols. And that is what the province is looking for. As far as you're concerned, do you think Toronto has reached the goals of getting to sort of graduate to stage 3? And do you expect to see that happen either next Monday or perhaps sooner?

De Villa: I do think that we've certainly seen declining trends with respect to new COVID-19 cases. We have a number of our monitoring indicators that are moving in the right direction. I think these are all positive things. In other jurisdictions, which we have to pay attention very carefully to, that even with fewer cases than what we've got right now, they have found themselves as they proceeded through reopening to have increased COVID-19 activity. This is why we've made some suggestions around how we can move to stage 3 safely and continue to maintain our progress.

This interview has been edited.