Nova Scotia is facing a ‘very difficult time’ of epidemics

CBC

We will never reach herd immunity against COVID-19, but that’s right, experts say

Every day, more and more Canadians are being vaccinated against COVID-19. Continuing this trend, it is said that we will soon reach a place where many people are not infected with the virus, which often dies due to lack of hosts for infections – providing indirect protection to the entire population, those who are not immune. The goal of “herd immunity” is often described around a corner, which signifies a return to pre-infection normalcy. But will we really go there? Probably not, say archaeologists and mathematicians who have been reading the latest numbers closely. At least, not at any time. These experts point to several key obstacles that stand in the way: the advent of new COVID-19 strains, the reluctance to vaccinate among adults and the fact that millions of children cannot be vaccinated. Even in an ideal situation, it turns the herd-immune range into a high bar. In practice, it may be unattainable. Workers are vaccinated at a clinic in Montreal. The exact percentage of the population that should be fully vaccinated or recovered from COVID-19 to achieve herd immunity is uncertain and may change. Recent estimates put the threshold at 80 or close to 90 percent. (Paul Siason / The Canadian Press) But that is not a cause for frustration. This is not herd immunity or bust. Unlike politicians, epidemiologists do not care about an exact number, which is difficult to back down. In practice, they say, the closer we get to that threshold – whatever it really is – the better. As more and more people become infected, life may begin to return to something more normal. Ashley Dwight, an epidemiologist and mathematical model with the Dalla Lana School of Public Health at the University of Toronto, has repeatedly directed calculations as to why herd immunity is so high – and for her, the results are very clear. “I think we will not achieve herd immunity,” he said. “But I don’t think that’s a bad thing.” The reason it seems out of reach for Duet is related to the cold, hard math. Watch | Why it is difficult to specify when herd immunity will be achieved: Herd-immunity is calculated using an equation with two main variables: the spread of a virus and the effectiveness of our immune response – a combination of vaccine and natural infection that comes from the population level. The exact percentage of the population that should be fully vaccinated or recovered from COVID-19 to achieve herd immunity is uncertain and may change. In previous epidemics, the threshold was estimated at about 70 percent. But the most recent estimates are as high as 80 or close to 90 percent. One of the biggest reasons for the increase is that new variants of the virus are estimated to be 50 to 60 percent more contagious than the original “wild type” strain. It only significantly raises the herd-immunity threshold. Even more complicated is the fact that no vaccine or natural infection can provide proper immunity. There are questions about the possibility of a vaccinated person carrying a small amount of the virus without any symptoms, but being able to spread the virus to those who are not immunocompromised. Similarly, there are questions about how long immunity from natural disasters will last and how it will support new variants. Another big challenge for the millions of children who have been left out of vaccines is that vaccines are only approved for Canadians 12 years of age and older. Health Canada has approved an application from Pfizer-Bioentech to use its vaccine in children under 12 years of age. (Previously it was only approved for people 16 years of age and older.) However, it leaves 4.8 million children – or 13 percent of the population – ineligible for any vaccine. The Pfizer-Bioendech vaccine for children under the age of 12 in Canada may soon be approved, but it will still accommodate 4.8 million children who are not eligible for any vaccine against Covit-19. (Evan Mitsui / CBC) Caroline Colliz, professor of mathematics at the University of Simon Fraser in Vancouver and head of research at Canada 150 on mathematics for evolution, infection and public health, says it plans to achieve immunity to any major whiplash. “We need to vaccinate children soon,” he said. Recent modeling collagen shows a significant reduction in the spread of the virus in a situation where children under the age of 10 can be vaccinated. In fact, if 70 percent of 10- to 19-year-olds are fully vaccinated, with a large number of adults, his modeling suggests that we can get close to herd immunity. Watch | Pfizer says the vaccine is safe and effective for children under 12: “It’s not interesting whether or not you knock right on that threshold. It’s really important to vaccinate those ages.” However, he warns that this modeling rests on many “convincing” assumptions. The scenarios studied by Coleidge suggest that natural immunity completely protects against relapse and does not diminish, that new variants do not reduce the effectiveness of vaccines and that a significant proportion of adults choose to be vaccinated. Vaccination reluctance among adults Without the ability to vaccinate children, herd immunologist at the University of Ottawa, Revat Dionanthan, says that near 100 percent of adults will need to be vaccinated to achieve herd immunity. He says this is impossible for a significant proportion of vaccine-reluctant Canadians. Revat Dionanthan, an epidemiologist at the University of Ottawa, says the same benefits of Canada’s herd immunity can be achieved by maintaining some degree of public health measures with growing vaccines. (Evan Mitsui / CBC) “Vaccine reluctance is a barrier,” Dionanthan said. “It’s not insurmountable, but it’s an obstacle.” In a recent poll, Canadians said they would heat up the vaccine and vaccinate as soon as they had the chance at a growing rate. But about 10 to 15 percent continue to say they will not accept a vaccine. On top of that, there are people on the fence. It is the behavior of the group in between that may ultimately determine how close we are to herd immunity – which is why various efforts are underway to encourage Canadians to get their shots. In the United States, vaccine reluctance is increasingly seen as a major and permanent barrier to herd immunity. Vaccine rolling south of the border began to accelerate, but as time went on it began to slow down and levels began to exceed supply requirements. Predicting the Future What is the Future of Canada? That’s something Paul Minshell reads closely. One, Minshel, founder of Scorsese Corporation, a corporate forecasting company based in Markham, has turned its extensive modeling software into the task of predicting where COVID-19 will go next. Scorsese’s models are constantly updated with the latest data, along with realistic assumptions about things we do not know – such as the actual effectiveness of vaccines against transmission and the actual level of vaccine reluctance we see among Canadians. Paul Minschel is the founder of Scorsese Corporation, a corporate forecasting company based in Ontario, whose advanced modeling software has transformed the task of predicting where COVID-19 will go next. (Evan Mitsui / CBC) Modeling boils everything down to one simple bottom line: the number of Canadians expected to be truly protected from COVID-19 by an effective vaccine or natural infection. Come October – while everyone who qualifies for the vaccine is expected to have a complete replenishment of the doses available to them – Scorsese’s latest modeling estimates that 25.2 million Canadians will be vaccinated, almost all with full doses. That’s 66 percent of the population. But this model makes some downward changes to the fact that vaccines are not perfect and that vaccinated individuals can spread the virus without symptoms. It makes some upward changes by including it in the rating for individuals who have not been affected by a natural infection but have “recovered immunity”. Add to this, according to Einschull, “the potential scenario for Canada … will be between 58 percent and 64 percent immunity this year – far below what the herds’ immunity needs.” A health worker administers the COVID-19 vaccine at a pop-up clinic in Toronto in April. The latest poll shows the growing rate of Canadians vaccinating as soon as they get the chance. But about 10 to 15 percent said they would not accept the vaccine. (Cole Burston / The Canadian Press) These results may seem disappointing, but Scorsin’s modeling predicts what effect this immunity will have on the severity of COVID-19. On that front, the future is very bright. “The good news is that things are going to improve significantly in the summer and fall, and more and more Canadians are getting vaccinated,” Minschell wrote in a recent study. Less of a finish line, more of a vision is what future Erin Strump fantasies about in late 2021. Strump, an associate professor of economics and epidemiology, biology and occupational health at McGill University in Montreal, believes the end of the epidemic is more like a drawn affair than a difficult stop. “We have to live with fewer people in stores and retail,” he said. “We’m going to keep wearing masks, we’m still going to work from home, some may be in the office. So it’s going to be fixed gradually.” Erin Strump, a health economist at McGill University in Montreal, says she believes the outcome of the epidemic appears to be more of a drag issue than a difficult one. (சிபிசி) மந்தை நோய் எதிர்ப்பு சக்தி, ஸ்ட்ரம்ப் கூறினார். ஒரு பூச்சு வரி: நாங்கள் அதைக் கடந்ததும், இனம் முடிந்தது. உண்மையில், COVID-19 க்கு எதிரான போராட்டத்தின் அடுத்த கட்டம் ஒரு பார்வை போன்றது: வைரஸ் வெவ்வேறு நேரங்களிலும் வெவ்வேறு இடங்களிலும் எரியும், மேலும் அதைத் தட்டிக் கேட்க நாம் அதற்கேற்ப பதிலளிக்க வேண்டும். ஆனால் ஒட்டுமொத்தமாக, இது கடந்த 14 மாதங்களில் இருந்ததைப் போல கடுமையாக இருக்காது. ஒட்டாவா பல்கலைக்கழகத்துடன் தியோனந்தன் கூறுகையில், வளர்ந்து வரும் தடுப்பூசி அளவுகளுடன் ஓரளவு பொது சுகாதார நடவடிக்கைகளை பராமரிப்பதன் மூலம் மந்தை நோய் எதிர்ப்பு சக்தியின் அதே நன்மைகளை நாம் அடைய முடியும். “நீண்ட காலமாக தணிக்கும் கருவிகளை வைத்திருக்க நாங்கள் தயாராக இருந்தால், பயனுள்ள மந்தை நோய் எதிர்ப்பு சக்தியை நாம் அடைய முடியும்” என்று தியோனந்தன் கூறினார். “மக்கள் மந்தை நோய் எதிர்ப்பு சக்தியைப் பற்றி நினைக்கும் போது அவர்கள் என்ன நினைக்கிறார்கள் என்பது மட்டுமல்ல, அனைவருக்கும் இலவசம் பற்றி அவர்கள் நினைக்கிறார்கள்.”

Sophia Harrison

Part time worker

I'm Sophia Harrison working as a part-time staff at the Costco since the past year until I become as an author at the iron blade, hope I can use my experiences with the supermarkets here.

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