Your questions answered by London's acting medical officer of health

It's been almost three weeks since the discovery of Omicron, the latest variant to emerge from the COVID-19 pandemic.

Ontario's science table shows Omicron has a reproduction rate roughly three times that of Delta — and a doubling time for cases of only three days. Officials around the world are now pivoting to boost protection measures. 

Dr. Alex Summers, the London region's acting medical officer of health, took your questions Thursday on London Morning. Here's some of what you had on your mind.

The following has been edited for clarity. 

Q: What are we seeing in the community? 

A: We're seeing exponential growth driven by the Omicron variant in our community, and I'm saddened and disheartened. We've been at this for a long time. But I'm encouraged by the fact that we as a community have rallied against this before, and that we will continue to do so. I also have a lot of sympathy for everyone who's realizing that yet again, this holiday season isn't going to feel like it used to in the past, nor like we would want it to. 

Q: When are more vaccines expected in the region? What are the plans to ramp up the mass vaccination clinics? 

A: We've been ramping up operations at the mass vaccine clinic all this past week. An additional 7,000 appointments were added between last Friday and Christmas Eve. And as we announced earlier this week, we're looking at significant additional capacity in early January. 

Our pharmacies in our region are also ramping up. We will see more and more product coming from the province to those pharmacies. So you will soon see a rapid flooding of the region with vaccine. The challenge is demand, obviously, has gone up very quickly, so it is going to be a challenge I think, particularly come Monday, when those 18 and older are eligible for people to find an appointment in the immediate future. We are continuing to add as many appointments as we can, but this is a very, very, very rapid ramp up and only so much is possible. But we're going as hard as we can. 

Q: My child and I are in self-isolation right now. Should I be booking my third vaccine on Monday? 

A: The most important thing right now for you is to remain in self-isolation. Once you're out of that self-isolation period, which is 10 days, then it would be appropriate to book a dose as soon as possible for your booster dose. The challenge is that the booster dose will still take five to seven days to get a robust response and so on. If you've been exposed before that, the booster dose unfortunately isn't going to make an impact at this point in time. But if you again stay in safe self-isolation and once you're out of that, immediately try and book an appointment as soon as possible.

Q: I received the AstraZeneca and Pfizer. What should I expect for a booster? 

A:  You and many others are in a position where you may have received different doses for your first and second. It doesn't matter which type of vaccine, whether it's Moderna or Pfizer, you receive for your third dose. Certainly, the difference in the effectiveness and the boost that you will get is marginal to the point that it does not matter. So you can get either Pfizer or Moderna for your third dose. Both will be effective at giving you that boost. 

Q: How long will it take for the booster to be effective? 

A: With all vaccines, we always give the immune system a two-week window to maximize the effectiveness. We do estimate that with this booster dose, early effectiveness is likely at the five to seven day mark after you receive the vaccine, with full protection again at that two week mark. 

Q: My child tested positive in October. Will he test positive on a take-home test now? 

A: We have seen people continue to test positive after having COVID 90 days or more after they had it. So if your child tested positive back in October, I would avoid using those tests right now. He may come back positive and it might just be the residual virus that's no longer replicating from when he was sick the first time. So I would hold off until after that 90 day mark from when he was diagnosed with COVID. 

Q: What settings have the majority of cases been coming from in recent days in London? Schools, workplaces, private gatherings? 

A: Three weeks ago, we were seeing a majority of our cases from Delta and they were happening in unvaccinated areas and in close social private gatherings. That is now changing. We are seeing cases and we are seeing so many cases that sometimes it's hard for us to pinpoint exactly where they're coming from. At this point, we are seeing cases from all walks, schools, workplaces, larger public gatherings that are indoors. 

Certainly any social environment where people are spending a lot of time indoors and potentially without a mask are at high risk. We've also seen significant transmission among amateur sports. The hockey tournament world is a blast because of the way that people get to spend time with each other, but it's also therefore an opportunity for Omicron to spread. So we are going to be again providing additional messages to folks: It's time to cancel those plans. It's time to take a pause on certain amateur sports. 

Q: When can we anticipate more rapid tests being offered free here in London?

I don't have a definitive answer. Speaking to the province yesterday, asking when those rapid tests might be arriving in our region, I don't have clarity on that timeline yet. Apologies. But we continue to advocate to the province for access to those tests in our region.