This week’s edition of Second Opinion is a collaboration with TBEN’s The Dose podcast, hosted by Dr. Brian Goldman.
As more regions of Canada enter lockdown and increase restrictions in a bid to contain the alarming spread of COVID-19, many government and public health officials point to two promising candidates for a vaccine against the coronavirus in the hope that the pandemic will one day end.
Over the past week, Pfizer and Moderna Inc. announced that their respective vaccines appeared to be 95% effective in Phase 3 clinical trials. These are two of the seven manufacturers with whom Canada has signed purchase agreements for millions of doses each.
Dr Howard Njoo, the country’s deputy chief public health officer, said if the vaccines are approved by Health Canada, he hopes the majority of Canadians can be vaccinated by the end of 2021.
But amid the optimism, a new vaccine naturally raises many questions, from how it works to who gets it first in a country of over 35 million people.
Here are some answers to these questions.
The two leading vaccines use a new technology called mRNA. What is that?
Traditionally, vaccines have been made using dead or “live attenuated” – or weakened – viruses to elicit an immune response in the body.
The vaccines from Pfizer and Moderna use pieces of genetic material – messenger RNA (mRNA) – from the coronavirus that causes COVID-19. This new technology has never been used before in commercial vaccines, said Dr. Jeff Kwong, acting director of the Center for Vaccine Preventable Diseases at the University of Toronto.
“In fact, the cells in your body make the proteins or antigens for the virus and then that stimulates the immune response,” he told TBEN podcast host Dr. Brian Goldman. The dose.
“So we don’t actually give people the virus, but we just donate the genetic material of the virus so that we can generate the antigens that will train our immune system to fight the virus.”
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The reason the mRNA vaccine results are coming out faster than more than 150 other coronavirus vaccine trials in different stages of development around the world, Kwong said, is because it is “much more effective.” to inject mRNA directly into the body than to produce antigens. by first injecting virus particles into eggs or cells. This is the most traditional method used by many other vaccine manufacturers.
Some social media posts claim that mRNA vaccines can damage or alter a person’s TBEN – is this true?
Absolutely not. It’s disinformation, Kwong said.
First, the mRNA vaccine does not enter the nucleus of cells, where most of the TBEN is located.
“It doesn’t affect our own genetic material. It’s just taking advantage of the machinery of our own body to generate the antigens,” he said. “So it’s a bit like borrowing our cells to make the antigens instead of making the antigens in cells or in eggs and then injecting them into the body.”
What are the steps between now and getting vaccinated against COVID-19?
Although very promising, the results are still preliminary, warns Kwong. Here’s what needs to happen:
Phase 3 of the clinical trials must be completed.
The data from the trials must be reviewed by each country’s regulatory body – here it is Health Canada – to independently ensure that the vaccine is both safe and effective.
If Health Canada approves the vaccine, the manufacturer must ship the doses to Canada, where it will be distributed to provinces and territories.
It is then up to the provinces and territories to follow their deployment plan, which they should develop now, to send the vaccine to public health authorities, doctors’ offices, hospitals, long-term care homes, at pharmacies or wherever vaccines are intended. be given to people who want one.
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How many doses of vaccine will we need in Canada?
Pfizer and Moderna vaccines require two doses, three weeks apart. It is likely that other successful candidate vaccines may also require multiple doses, experts say. With a population of over 35 million people in Canada, that means over 70 million doses in total.
Although the agreements that Canada has signed with manufacturers cover more than this amount, they will not all happen at the same time. They are likely to arrive in staggered shipments throughout 2021 as they are made, Kwong said.
So who gets vaccinated first?
The National Advisory Committee on Immunization (NACI), an independent body that advises the Public Health Agency of Canada, recently issued “preliminary guidelines” on how to prioritize immunization against COVID-19 once that a vaccine is approved.
According to NACI, the first vaccines should go to:
- People at high risk of death or serious illness from COVID-19 (including the elderly and those with high-risk health conditions).
- People most likely to transmit COVID-19 to people at high risk (this may include health workers, support workers, or people living with people at high risk).
- Workers essential to maintain the response to COVID-19 or provide primary care to patients with COVID-19.
- People “contributing to the maintenance of other services essential to the functioning of society”. These workers have yet to be defined in discussions between federal, provincial and territorial governments, NACI said, but could include police, firefighters or grocery store staff.
- People who live or work in conditions that put them at a higher risk of infection or in which infection could have “disproportionate consequences, including indigenous communities”.
What about the children?
On November 17, the American Academy of Pediatrics issued a press release calling for children to be immediately included in clinical trials of the COVID-19 vaccine to ensure they “are not excluded from potentially life-saving vaccines. “.
Pfizer has “recently” started enrolling children as young as 12, the academy said.
“Children are not little adults. We need to include children in trials as soon as it is safe to do so,” said Dr Yvonne Maldonado, chair of the academy’s committee on infectious diseases, in the communicated.
“This research is taking time. If it does not start soon, it is unlikely that a vaccine will be available for children until the next school year.”
TBEN News reached out to the Canadian Pediatric Society for comment, but was unable to respond before the deadline.
However, Kwong and Dr Jeffrey Pernica, chief of the division of pediatric infectious diseases at McMaster University, agreed with the American organization’s position.
“COVID-19 rarely causes serious illness in children – but the pandemic has had significant effects on the health of children and youth,” Pernica said in an email to TBEN News.
“If we are to develop true herd immunity, we will also need to vaccinate children,” Pernica said. “We absolutely need to have data on their safety and efficacy in children.
“A majority of parents are unlikely to wish to immunize their children with vaccine products that have not been verified for safety in this age group.”
What are the logistical challenges of delivering vaccines to Canadians?
The number one challenge, Kwong said, is the sheer volume of supply needed.
“The hope is that we can get everyone who wants to get vaccinated as quickly as possible,” he said.
Once the supply arrives, Kwong estimates that between the doctors, public health nurses and pharmacists (in provinces where they are authorized to give vaccinations), there will be enough people to administer the vaccination during 2021. Military support would be “a welcome help,” he said – particularly in helping the vaccine reach remote areas.
A major challenge with the Pfizer vaccine, however, is that it must be stored at -70 ° C – a much cooler temperature than is possible in most freezers. (Moderna said her vaccine can be stored in a refrigerator for up to a month.)
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The Public Health Agency of Canada is ensuring that the need for ultra-freezers does not delay the vaccination process, said spokesperson Eric Morrissette.
The agency is working with provinces and territories to examine where equipment currently exists – including “the ability to transport and safely store ultra-low temperature and frozen vaccines,” Morrissette said in an email Friday.
“Any capacity gap will be addressed to ensure the safe and timely delivery of vaccines.” he said.
Once vaccinated, will we be immune to COVID-19 for life?
It’s still unknown, Kwong said, because it’s been less than a year since the virus first appeared on anyone’s radar. Although clinical trials have shown a high rate of immunity, there really is no way of knowing how long it lasts until people are vaccinated in the real world and time passes.
“There are a lot of vaccines that basically offer lifelong protection, and some don’t,” Dr. Lynora Saxinger, an infectious disease specialist at the University of Alberta, said in an email to TBEN News.
However, Saxinger is encouraged by the messenger RNA technology in the Pfizer and Moderna vaccines.
“The mRNA vaccines are basically designed to code your own cells to make the virus spike protein so your immune system really sees it in a way that mimics natural infection,” she says. “This should increase the likelihood of a good long-term response.”
Even if this is not the case, multiple doses over the years are sometimes needed, even in existing vaccines. A booster is needed every 10 years for tetanus, for example. The flu shot requires a vaccine every year.
“A good thing about vaccines is that booster strategies can be used if they are not found to have a lasting effect.” Said Saxinger.
Additionally, more vaccine candidates of different types are expected to be successful in the coming months, she said, and some may prove to be more effective in some people than others.
“It’s good to have a menu to choose from,” Saxinger said.
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