What are the current risks of COVID-19 and what’s next? Ontario science table leader responds – .

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What are the current risks of COVID-19 and what’s next? Ontario science table leader responds – .


We’ve heard the names – Alpha, Beta, Delta, Gamma – all of the worrying variants when it comes to COVID.

And just a few days ago, a new variant surfaced in South Africa – B.1.1.529, now called Omicron by the WHO – which is even more transmissible than Delta, which has already crushed its competitors and is become dominant in Canada and the rest of the world.

Delta’s transmissibility doubled cases in one week in one part of Ontario after provincial restrictions were lifted.

Now cases are increasing in Toronto as well and there is cause for concern.

“In Delta’s presence, for those who are not yet fully vaccinated, there is no escape,” said Dr. Peter Juni, epidemiologist and scientific director of the Ontario COVID-19 Science Advisory Table. A variant case causes an average of seven other infections in the unvaccinated, if no public health measures are taken.

“Either you are immunized by vaccination. It’s the easy way out, ”Juni said. “Or by infection. This is the risky route.

Juni says at least 95% of the population would need to be vaccinated to achieve herd immunity because of Delta’s “impressive” reproduction numbers opposed to vaccines that protect 85%.

There is no evidence yet to suggest that the newly discovered Omicron variant is in Canada.

What is known so far is that Omicron has outperformed Delta faster than Delta has outperformed Alpha, Juni says.

And the new variant probably has an advantage on two fronts – it is more transmissible than Delta and more easily evades the immune system, even in people who have been vaccinated or who have contracted COVID.

On Friday, the federal government said foreigners who visited seven southern African countries – South Africa, Mozambique, Botswana, Zimbabwe, Lesotho, Eswatini and Namibia – in the past 14 days would be banned from entering the Canada.

And Canadian citizens and permanent residents, or others with the right to enter Canada, who have visited these countries should be tested on arrival and quarantined until they receive a result of negative test.

We chat with Juni about groundbreaking cases, declining immunity, and how to protect each other while on vacation. Answers have been edited for clarity and length.

Do we know what is causing the current increase in COVID cases? Are these unvaccinated people, breakthrough cases, the transmissibility of the Delta variant, or a combination of all three?

It is a combination of the three. Over 85% of the eligible population is fully vaccinated. Even though the vaccine reduces your risk of getting infected about six times, you will still see a lot of breakthrough cases in those vaccinated. It shouldn’t confuse people, breakthroughs are absolutely normal. Currently, about half of infections come from the 85 percent who are fully vaccinated and the other half from the 15 percent who are not vaccinated. If 100 percent of the entire population were vaccinated, you would only see cases in the vaccinated. But that wouldn’t mean the vaccine isn’t working.

Unvaccinated people continue to be about six times more likely to be infected in the province right now. And they continue to be about 20 times more likely to end up in hospital and 25 times more likely to end up in intensive care.

Why do cases of rupture occur?

Delta is highly transmissible and partially evades the immune system because our vaccines introduce a spike protein through the mRNA sequence in the body which is always like that of the wild type coronavirus. Additionally, current vaccines are intramuscular, so the type of antibodies we generate – IgG antibodies – work systemically, preventing hospitalization, ICU admission and death, but sometimes allowing the virus to enter. in the body and cause milder infections in cases of breakthrough. If we had a nasal spray for vaccination, we would generate IgA antibodies, which protect the lining of the upper respiratory tract, and we might be better protected against infections. Nasal sprays for vaccination are under discussion right now, so they are still in a few years.

Do we know how much our immunity decreases?

In Ontario, the extent of vaccine protection has declined a bit, from around 85 to 87 percent initially to around 80 to 82 percent, according to our dashboard. But it’s not just because of the decline (of immunity). Thanks to vaccination certificates, it is also because vaccinated people are now more free to expose themselves. They can go to restaurants and eat in a crowded dining room, while unvaccinated people cannot. Thus, we believe that the revolutionary cases that are occurring now may be due to a combination of exposure as well as a slight decrease in immunity.

Why do we need a third dose?

Vaccines provide excellent protection against serious illness, but immunity will wane a bit over time. Therefore, a third dose will start to be important first in older groups and more vulnerable people who are already eligible for the vaccine. And if we think about the continued control of the pandemic, younger age groups will also need to receive a third injection. We don’t yet know where the sweet spot is, what type of age we want to use. But the injections will not only better protect everyone against hospital and intensive care admissions and deaths, but also provide neutralizing immunity against infections. This means that you have such high antibody levels that even if the virus enters the body, it is immediately captured and neutralized by the IgG antibodies in the immune system.

In the presence of this new variant of Omicron, anyone who can receive a third dose should receive one immediately because each further improvement in the immune response will be even more important for Omicron than for Delta.

Will the third dose stop the breakthrough cases?

The third dose will do everything, including a reduction in breakthrough cases, as we can see from Israel, when it comes to Delta. (Note: A fourth wave in Israel, which led to a sharp rise in infections among those vaccinated last fall, was brought under control with third doses and public health measures.) But Keep in mind that Israel had a three to four week interval between the first and second dose whereas we had on average much longer intervals which is to our advantage. Longer intervals between doses may mean that the immune system matures a bit more and the immune response after the second is more pronounced.

Why should we make specific Delta or Omicron vaccines when we have had so many variants? Is it because we can make mRNA vaccines quickly, or is it because we think Delta or Omicron will be around for a long time?

I figured Delta would be around for a long time unless he got picked up by another variant that has more mutations and makes him even more easily transmissible, which seemed pretty difficult to achieve until two days ago. Basically, if you have a breeding number of seven, like Delta, you’re pretty good as a virus. But now Omicron has managed to outperform Delta – it’s real-time evolution.

Now we will have to see what types of vaccines will be developed in the longer term using mRNA technology from Pfizer and Moderna to achieve better protection against Delta, against Omicron and against future versions of these two worrying variants with even more mutations. For now, we’ll stick with existing mRNA vaccines, which offer excellent protection after two doses, and even more protection after three doses.

We see the cases increasing since the reopening. What do you think of these inconsistent masking policies, where we are forced to wear masks while shopping but not when sitting side by side in a crowded cinema watching a movie?

I think this is a real problem. People use eating and drinking in places other than meals as a reason not to wear their masks. This is fundamentally wrong. So what we would need to basically realize is that the staff at sports arenas, cinemas, et cetera, do the same as flight attendants. Talking to people say sorry, you only take your mask off quickly when you are drinking or eating and then you have to put it back on. It could make all the difference.

What would you say to people with the holidays coming? Should we be singing in church, shopping in crowded stores, having holiday parties indoors?

Look at Europe and look at the mess they have. When you see that, you notice that with the temperatures dropping, people moving indoors, we all tend to have more problems than before. This is one of the reasons we are starting to see the number of cases increase. The transmission of this virus is airborne, so it likes people to be in crowded spaces that are not so well ventilated. So what’s important is that everyone should help control this pandemic by decreasing their contacts a bit. Ask yourself: do I really need to go to the five dinners I have been invited to? And do I really want to go to that crowded restaurant or could I just go somewhere that is really well ventilated and less crowded? And do I really need to see all of my friends or can I narrow my circle of friends that I have close contact with to maybe 10? But not 50 or 100. And singing in church is not really a good idea. Everything helps.

What about travel outside of Canada?

I think the risks associated with travel are not that different nationally and internationally, unless you go to places that have significantly higher numbers than us, which for Ontarians right now is essentially the rest of the northern hemisphere. We look extremely good compared to almost everyone in the world. Being fully vaccinated and having at least one negative PCR test or rapid antigen test for people coming to Canada means a powerful reduction in the risk of introducing infections and new variants into the country.

The new Omicron variant, however, means additional requirements will be needed for travelers from high-risk countries, which are currently South Africa and neighboring countries and possibly soon the entire continent. We may need to add additional testing, five or seven days after arrival, as well as quarantine requirements.

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