What you need to know as we approach a COVID-19 vaccine

In the past week, both Pfizer and Moderna Inc. announced that their respective vaccines appeared to be 95% effective in Phase 3 clinical trials. They are two of the seven manufacturers with which Canada has signed purchase agreements for millions of doses each. .

Dr Howard Njoo, the country’s deputy chief of public health, said that if the vaccines are approved by Health Canada, he hopes most 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 front-line vaccines use a new technology called mRNA. What is that?

Traditionally, vaccines have been made using dead or “live attenuated” – or weakened – viruses to provoke an immune response in the body.

Both Pfizer’s and Moderna’s vaccines use bits of genetic material – messenger RNA (mRNA) – from the coronavirus that causes COVID-19. This new technology has never been used in commercial vaccines before, said Dr. Jeff Kwong, acting director of the Center for Vaccine Preventable Diseases at the University of Toronto.

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“It actually causes the cells in your body to make the proteins or antigens of the virus and so this stimulates the immune response,” he said. Brian Goldman, host of the CBC podcast The dose.

“So we’re not actually giving the virus to people, we’re just providing the genetic material of the virus in order to generate the antigens that will train our immune systems to fight the virus.”

The reason mRNA vaccine results are coming out faster than more than 150 other coronavirus vaccine studies in various stages of development around the world, Kwong said, is because “it’s much more efficient” to inject the mRNA. directly into the body which produce antigens by first injecting virus particles into eggs or cells. This is the more traditional method used by many other vaccine manufacturers.

Some social media posts claim that mRNA vaccines can damage or modify a person’s DNA – is that true?

Absolutely not. This is misinformation, Kwong said.

First of all, the mRNA vaccine does not enter the cell nucleus, where most of the DNA is located.

“It doesn’t affect our genetic material. It’s just taking advantage of our body’s mechanism to generate the antigens,” he said. “So it’s kind of like borrowing our cells to make the antigens instead of making the antigens in the cells or eggs and then injecting them into the body.”

What are the steps from now to getting COVID-19 vaccination?

While very promising, the results are still preliminary, warns Kwong. Here’s what needs to happen:

1. Phase 3 of the clinical trials must be completed.

2. The study data must be reviewed by the regulator for each country – here, it’s Health Canada – to independently ensure that the vaccine is safe and effective.

3. If Health Canada approves the vaccine, the manufacturer must ship the doses to Canada, where they will be distributed to provinces and territories.

4. It is therefore up to the provinces and territories to follow their implementation plan, which they should develop now, to bring the vaccine to public health authorities, doctors’ offices, hospitals, long-term care homes, pharmacies, or wherever the vaccines. be given to people who want one.

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How many doses of the vaccine will we need in Canada?

Both Pfizer and Moderna vaccines require two doses, taken three weeks apart. Other successful vaccine candidates are also likely to require multiple doses, experts say. With a population of over 35 million people in Canada, that means more than 70 million doses in total.

While the agreements Canada has signed with manufacturers don’t cover that amount, they won’t come all at once. They are likely to arrive in staggered shipments throughout 2021 as they are produced, 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 released a “preliminary guide” on how to prioritize immunization against COVID-19 once a vaccine.

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 people who have high-risk health conditions).
• People who are more likely to transmit COVID-19 to high-risk people (this could include health care workers, support workers, or people living with high-risk people).
• Essential workers to maintain the COVID-19 response or provide frontline care for COVID-19 patients.
• People “who contribute to the maintenance of other essential services for the functioning of the company”. These workers have yet to be defined in discussions between federal, provincial and territorial governments, the NACI said, but they could include police, firefighters, or grocery store staff.
• People who live or work in conditions that put them at greater risk of infection, or where the infection could have “disproportionate consequences, including indigenous communities”.

And 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 “only recently” began enrolling 12-year-olds, 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 infectious disease committee, in the statement.

“This research takes time. If it doesn’t start early, it will be less likely that a vaccine will be available for children before the next school year.”

CBC News reached out to the Canadian Pediatric Society for comment, but was unable to respond by the deadline.

However, both Kwong and Dr. Jeffrey Pernica, head of the division of pediatric infectious diseases at McMaster University, agreed with the American organization’s position.

“COVID-19 only rarely causes serious illness in children, but the pandemic has had a significant impact on the health of children and young people,” Pernica said in an email to CBC News.

“If we want to develop true herd immunity, we will have to immunize children too,” Pernica said. “We absolutely need to have data on their safety and efficacy in children.

“Most parents will likely not want to immunize their children with vaccine products that have not been tested to be safe in that age group.”

What are the logistical challenges of providing vaccines to Canadians?

Challenge number one, 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 supplies arrive, Kwong believes that among doctors, public health nurses and pharmacists (in the provinces where they are authorized to provide vaccinations), there will be enough people to administer the vaccination over the course of 2021. Military support would be “assistance. welcome “. “he said, specifically to help the vaccine reach remote areas.

A key challenge with the Pfizer vaccine, however, is that it needs to be kept at -70 ° C, a much colder temperature than is possible in most freezers. (Moderna said her vaccine can be stored in the refrigerator for up to a month.)

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Canada’s Public Health Agency is ensuring that the need for ultra-freezers does not hinder the vaccination process, spokesman Eric Morrissette said.

The agency is working with provinces and territories to examine where the equipment currently exists, including “the ability to safely transport and store ultra-low temperature and frozen vaccines,” Morrissette said in an email Friday.

“Any capacity gaps 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?

This is still unknown, Kwong said, because it has been less than a year since the virus appeared on someone’s radar. Although clinical studies have shown a high rate of immunity achievement, there is really no way of knowing how long it lasts until people get vaccinated in the real world and more time goes by.

“There are many vaccines that offer essentially lifelong protection, and some that don’t,” Dr. Lynora Saxinger, an infectious disease specialist at the University of Alberta, told CBC News.

However, Saxinger is encouraged by messenger RNA technology in the Pfizer and Moderna vaccines.

“MRNA vaccines are basically designed to give your cells a code to make the virus spike the protein so that the immune system really sees it in a way that mimics natural infection,” he said. “This should increase the likelihood of a good long-term response.”

Even if not, multiple doses are sometimes needed over the years in existing vaccines. For example, a booster shot is needed every 10 years for tetanus. The flu shot requires one injection every year.

“A nice thing about vaccines is that booster strategies can be used if they are not shown to have a lasting effect.” Saxinger said.

Additionally, more vaccine candidates of different types are expected to be successful in the coming months, he said, and some may prove more effective in some people than others.

“It’s nice to have a menu to choose from,” Saxinger said.

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