I call this meeting to order.
Welcome, everyone, to meeting number 24 of the House of Commons Standing Committee on Health. The committee is meeting today to study the emergency situation facing Canadians in light of the second wave of the COVID-19 pandemic.
I would like to remind everyone that everyone has the right to participate in these proceedings in the official language of their choice. In the event that there is difficulty in hearing translations, please bring it to our attention as soon as possible so that the matter can be resolved.
I would like to welcome the witnesses at this point. From the national advisory committee on immunization, we have Dr. Caroline Quach-Thanh, chair and professor, Université de Montréal. With the Department of Health, we have Dr. Marc Berthiaume, director, health and food branch, therapeutic products directorate, bureau of medical sciences. From the Public Health Agency of Canada, we have Ms. Kimberly Elmslie, vice-president, immunization branch; Dr. Howard Njoo, deputy chief public health officer; and Dr. Guillaume Poliquin, acting scientific director general, national microbiology laboratory.
I would just advise the speakers that I will be using these cards to indicate that your time is almost up. I will typically put up the yellow one about one minute before your time is up. I will use the red one when your time is up, and if you see it, please wrap up in due course.
With that, we will carry on with our presentations. We will start with Dr. Caroline Quach-Thanh.
Doctor, please go ahead for 10 minutes.
Mr. Chair and members of the Standing Committee on Health, thank you for inviting me to speak to you again, this time regarding the use of the AstraZeneca vaccine for adults aged 65 and older.
The recommendations of the National Advisory Committee on Immunization, or NACI, issued on March 1, 2021, were as follows.
A complete and currently authorized COVID-19 vaccine series should be offered to individuals in the authorized age group without contraindications to the vaccine. In the context of a limited vaccine supply, initial doses of the messenger RNA COVID-19 vaccine should be prioritized for the key populations listed in the NACI's “Guidance on the prioritization of initial doses of COVID-19 vaccine(s)” document.
Given the superior efficacy reported in clinical trials, the messenger RNA COVID-19 vaccine is preferentially recommended for individuals in the authorized age group without contraindications, especially for those at highest risk of severe illness and death and at highest risk of exposure to COVID-19.
In the context of a limited vaccine supply, the AstraZeneca COVID-19 vaccine may be offered to individuals aged 18 to 64 without contraindications if the advantages of earlier vaccination outweigh the limitations of vaccinating with a less efficacious vaccine; the ease of transport, storage and handling of this vaccine facilitates access to vaccination that may otherwise be challenging; and informed consent includes a discussion about current vaccine options and the timing of future vaccine options.
At the time the NACI recommendations were made, the committee had assessed the data from the randomized controlled trials submitted by the manufacturer, which meant two phase one/two studies, one phase two/three study, and one phase three study, as well as a real-world effectiveness study performed in Scotland by Vasileiou and colleagues entitled “Effectiveness of first dose of COVID-19 vaccines against hospital admissions in Scotland: national prospective cohort study of 5.4 million people”, which is a preprint. This means it is not yet reviewed by peers.
Data from an ongoing phase three trial in the U.S. are not yet available. Of note, the FDA is waiting on these results to make a decision on authorization. The clinical trials data submitted were challenging to interpret, as there was use of both a low dose/standard dose and a standard dose/standard dose vaccine regimen in trials, a varied interval between doses, and the recruitments of progressively older study participants after the initial focus was put on adults 18 to 55 years old.
The estimates of vaccine efficacy against confirmed COVID-19 cases occurring at least 15 days after dose two, by dosing interval, suggested an increase in vaccine efficacy with an increasing interval between doses of vaccine, but confidence intervals are wide and overlap. As a recap, a 95% confidence interval means that we are 95% confident that the true value—in this case, vaccine efficacy—will fall within these boundaries.
When confidence intervals around a point estimate overlap in a given study, it means that the two estimates could possibly be the same. In this case, the vaccine efficacy with a dosing interval of four to eight weeks was 55.7%, with a 95% confidence interval going from 39% to 68%, while the vaccine efficacy of an interval greater than 12 weeks was 81.6%, with a 95% confidence interval from 47% to 94%, so both intervals are overlapping.
A subgroup analysis of vaccine efficacy against the first occurrence of confirmed COVID-19 at least 15 days after dose two showed that, for all studied intervals between doses, the point estimate for vaccine efficacy ranged around 60% for the younger age group—that means 18 to 64—with a confidence interval that did not include zero. This means a vaccine efficacy is really there, compared with 43% for 65 years and over, with a wide confidence interval that includes zero, meaning that the actual vaccine efficacy could be null.
Based on these data, NACI felt that it was safest, given the availability of two other mRNA vaccines that were highly efficacious in people 65 years and over, to recommend the mRNA vaccines in that age group and not recommend the AstraZeneca vaccine for 65 years and over. This is awaiting further data, including the clinical trial that is ongoing in the U.S.
NACI also reviewed the Scottish paper, as these data were available. This study, which has not yet been peer-reviewed, is a real-time prospective observational cohort with national-level coverage in Scotland, using administrative data that are all linked. The cohort included 5.4 million people. The authors studied the first doses of either the Pfizer-BioNTech or AstraZeneca vaccines. The authors assessed the effectiveness—the effect of the vaccine in real life, as opposed to efficacy, which studies the effect in a randomized clinical trial—against hospital admission with COVID-19 as the main diagnosis within 28 days of a positive PCR for SARS-CoV-2.
During the study period, 35% of participants were vaccinated, mainly among the first priority groups aged 80 years and over. Younger individuals had a higher uptake of the Pfizer vaccine, while those 80 years and over had a higher uptake of the AstraZeneca vaccine. The authors reported a statistically significant adjusted vaccine effectiveness against COVID-19-related admissions in those who received a first dose of either vaccine, which increased over time until a peak at day 28 to day 34 post-vaccination.
Although these data seem promising, the committee was not able to explain why the vaccine effectiveness was so high so early on. On days 7 to 13, the reported effectiveness was already 70%, with a 95% confidence interval from 63% to 76%. This raised questions about the study's methodological validity. Moreover, given the context of the targeted vaccination and study design, NACI considered that there was a high risk of bias and that vaccinated individuals were likely not comparable to unvaccinated individuals. Given these uncertainties, NACI decided that this study was not solid enough to change policy, and kept its recommendation not to use the AstraZeneca vaccine for those aged 65-plus at that point in time.
In the short time since NACI's recommendations were published, two other real-world effectiveness studies have been preprinted. The committee met yesterday, on March 10, to discuss them and decide if these new data would change recommendations. An updated statement, which will include the real-world evidence, will be released as soon as possible.
Regarding Health Canada's authorization, it's important to understand that, while both Health Canada and the National Advisory Committee on Immunization report to the , they don't have a reporting relationship with each other. Health Canada's role is to authorize specific indications for use that are expected to be safe, immunogenic, efficacious, and of suitable quality for individuals. To do so, it reviews preclinical data, clinical trial data, and manufacturing information submitted by manufacturers, along with post-market surveillance data.
Once a vaccine is authorized, the NACI becomes involved. The NACI's role as a technical committee and advisory body is to recommend vaccination strategies to promote health, prevent and control infectious diseases, and prepare for or respond to public health emergencies. The NACI does this by reviewing all relevant and available evidence on the vaccines in question in the context of public health considerations, and then taking into account not only vaccine characteristics and the burden of disease, but also the concepts of ethics, equity, acceptability, and feasibility. The NACI regularly relies on the support of mathematical modellers to assess the effects of various strategies.
The NACI can make off-label recommendations when there's a clear need supported by a public health ethical analysis.
In this particular context, NACI considered the advantages of administering a COVID-19 vaccine earlier to Canadians against the limitations of administering a vaccine that, based on available data, is less efficacious. Based on mathematical modelling, various strategies were studied. In clinical trials, mRNA COVID-19 vaccines demonstrated higher efficacy than the AstraZeneca vaccine. In the context of limited supply, NACI, however, considered additional factors when assessing options for COVID-19 immunization.
Internal modelling reviewed by NACI, based on Canadian supply projections, indicated that a program including both mRNA vaccines and the AstraZeneca COVID-19 vaccine could have short-term public health benefits—preventing symptomatic disease, hospitalization and death—when the AstraZeneca COVID-19 vaccine is offered earlier to adults who are 18 to 54 instead of waiting for an mRNA vaccine, during periods of epidemic transmission. The public health benefits of offering the AstraZeneca vaccine earlier only to individuals who are 55 to 64 years old were less certain, given their shorter expected wait times to get mRNA vaccines. Modelling assumed no impact of vaccines on preventing transmission, as evidence of this is not yet available.
The population that received a lower-efficacy COVID-19 vaccine will have protection against COVID-19 disease earlier than if they had waited for mRNA vaccines to be available. However, these populations may ultimately have lower protection, depending on the duration of protection of both vaccines, as a larger proportion of the population will remain susceptible. Depending on vaccination strategies, it could potentially exacerbate health inequities if this potential harm is not considered when implementing the vaccine program in populations that experience intersecting risk factors for severe disease and exposure.
The mRNA COVID-19 vaccines have more challenging storage and transportation requirements than the AstraZeneca COVID vaccine, which may limit the venues where the vaccine may be offered. Vaccine hesitancy may be reduced by offering the COVID-19 vaccine in more convenient locations. That element was deemed important in the decision as to who should receive the AstraZeneca vaccine.
I hope that this explanation has helped the committee understand the thought process behind the NACI's decisions and recommendations issued on March 1.
Thank you for your attention. I would be happy to answer your questions.
Good evening, Mr. Chair.
My name is Dr. Marc Berthiaume, and I am the director of the bureau of medical sciences at Health Canada, health products and food branch.
Thank you for inviting me to appear before the committee today. I appreciate this opportunity to discuss Health Canada's high standards for the vaccine approval process and, in particular, to address questions regarding the approval of the AstraZeneca vaccine for people over 65 years of age.
I want to begin by emphasizing that Health Canada authorizes vaccines only if they meet the department's stringent safety, efficacy and quality requirements.
As with the other vaccines, Health Canada conducted independent and thorough scientific reviews to determine that the benefits outweigh the risks for the AstraZeneca COVID-19 vaccine, which was developed in partnership with Oxford University, as well as the Serum Institute of India's version of the AstraZeneca vaccine, sponsored in Canada by Verity Pharmaceuticals.
Health Canada has rigorously evaluated the data available from clinical trials and real-world evidence, and determined that this vaccine is safe to be administered to adults 18 years of age and older.
We also collaborated with the European Medicines Agency on the review of the AstraZeneca vaccine, as part of its open process. This initiative makes it possible for trusted regulatory authorities outside of the European Union, such as Health Canada, to work together and share information throughout the review process.
All regulatory authorities that have authorized the AstraZeneca vaccine have granted unrestricted adult indications.
Even though limited information from clinical trials is available to calculate its efficacy in people 65 years of age and older, Health Canada's authorization for a broad adult population has taken the available data on immune responses into consideration. There is emerging promising evidence that is beginning to be reported from studies on the real-world use of the vaccine, along with data on the safety profile of the vaccine from millions of people who have received it.
In addition to the encouraging real-world evidence that is already showing benefits with respect to outcomes such as hospitalization, it is important to note that there were no safety issues in this age group. There were no issues in the clinical studies, where about 700 people over the age of 65 were administered the vaccine, nor in the large numbers of seniors who have been vaccinated to date in other countries that have also authorized the AstraZeneca vaccine and are administering it to people over the age of 65.
Specifically, during the first summary of the safety reporting period of January 1-31, 2021, safety data was available for over 3.7 million people who received the vaccine, with no safety issues identified. A safety signal of anaphylaxis has more recently emerged, which is currently being added to the product monograph.
Health Canada is aware of the reports in Europe of adverse events, including fatalities, following immunization with the AstraZeneca vaccine, specifically thromboembolic events such as blood clots. We are monitoring and working closely with national regulators to gather information, including the European Medicines Agency, whose safety committee has initiated an accelerated investigation. At this time, we do not believe this is a new safety issue that will impact the deployment of the vaccine in Canada. These sorts of events demonstrate that our rigorous safety system works well to identify and quickly start to investigate issues.
Health Canada is reassuring Canadians that the benefits of vaccination outweigh the risks. We expect further information from ongoing clinical trials and post-market monitoring in the coming months. If there are additional changes required with regard to safety or efficacy, Health Canada will take the necessary actions.
In the meantime, the department has been transparent regarding the data that was considered, and has reflected the limited data on efficacy for those over the age of 65 in its regulatory document, including the product monograph.
I want to point out that all COVID-19 vaccines were authorized in Canada under an interim order approved in September 2020. This enables us to speed up the review of COVID-19 treatments and vaccines, while maintaining a high level of scientific review.
With this interim order, Health Canada can approve a new vaccine based on available evidence with more agile administrative and application requirements. The interim order also allows for rolling reviews, which lets a vaccine manufacturer submit its request for authorization before it has completed all the clinical trials. This means that it can submit required data as the data becomes available. The interim order also gives Health Canada the authority to impose terms and conditions to require the manufacturer to continue providing information on the safety, efficacy and quality of the vaccine once marketed.
Additionally, we have a strong post-market safety surveillance system to monitor the safety of COVID-19 vaccines. Once a vaccine is on the market, Health Canada and the Public Health Agency of Canada monitor for any adverse events after immunization in collaboration with the provinces and territories and the manufacturer. The interim order provides the authority to impose terms and conditions on any authorization at any time, such as additional assessments of safety information. We'll take swift action if safety concerns are identified.
All Health Canada's regulatory decisions are independent and based solely on scientific data and evidence. Our COVID-19 vaccine review teams are comprised of experienced scientific and regulatory experts, including scientists and physicians with many years of experience in reviewing vaccines. Together, these measures have allowed Health Canada to authorize several clinical trials in Canada for COVID-19 vaccines, as well as for five vaccines: Pfizer-BioNTech, Moderna, AstraZeneca, the AstraZeneca version produced by the Serum Institute in India, and Janssen.
As part of our ongoing commitment to openness and transparency, Health Canada has published detailed information about the authorized COVID-19 vaccines on its COVID-19 vaccines and treatments portal. This information includes Canadian product monographs and regulatory decision summaries that provide a high-level summary of the evidence reviewed to support vaccine authorization.
Health Canada and the Public Health Agency of Canada provide weekly updates on reported adverse events following immunization. Our response to the pandemic is being guided by the latest science and research. We're also continuing to closely monitor the emerging viral variants and to work with manufacturers and international regulators in order to assess the impact of the new variants on vaccine efficacy and provide guidance to manufacturers.
Health Canada, together with the Access Consortium that also includes our regulatory counterparts in the United Kingdom, Australia, Switzerland and Singapore, has developed and published guidelines for the industry regarding our common regulatory approach to authorizing updates to existing vaccines in order to combat new variants.
Canadians can rest assured that the review process for each vaccine has been rigorous and that systems are in place to continue to monitor the safety and efficacy of authorized COVID-19 vaccines. The vaccines play a critical role in Canada's response to the pandemic and fight against COVID-19. The authorization of these additional vaccines, which meet Health Canada's rigorous safety, efficacy and quality standards, provides additional tools to fight this pandemic as quickly as possible.
Thank you very much, Mr. Chair. Good evening, members.
This evening I will be speaking about the role of Canada's national advisory committee on immunization in the immunization system in our country. NACI, as you know, is an expert, external body that provides independent advice to the Public Health Agency of Canada on the optimal use of authorized vaccines in Canada. NACI has been operating for over 50 years as the country's national immunization technical advisory group, and it is widely respected by provinces and territories and internationally.
The committee is made up of experts from across Canada in the fields of pediatrics, infectious diseases, immunology, pharmacy, nursing, epidemiology, pharmacoeconomics, social sciences and public health. In the context of COVID-19, Canada's federal, provincial and territorial governments utilize the advice of NACI as the authoritative body on pandemic vaccine prioritization and vaccine public health program design. Its recommendations are designed to support the pandemic public health response goals of reducing serious illness and overall death while minimizing societal disruption as a result of COVID-19.
NACI's COVID-19 advice is focused on the strategic prioritization of vaccines and specific vaccine guidance and ranking of products for clinical use. Its recommendations inform federal, provincial and territorial governments' planning for the efficient, effective and equitable allocation of COVID-19 vaccines. NACI thoroughly reviews available evidence when developing its recommendations. This includes the consideration of vaccine characteristics, such as safety, efficacy, immunogenicity and effectiveness. NACI also incorporates programmatic factors such as economics, ethics, equity, feasibility and acceptability.
NACI's guidance is advisory in nature. Immunization program planning and delivery decisions fall under provincial and territorial jurisdiction. The provinces and territories ultimately determine how to use authorized COVID-19 vaccines based on jurisdictional needs and circumstances, including local epidemiology, public health considerations, health care system capacity and vaccine management logistics.
NACI is supported by a secretariat housed within the Public Health Agency of Canada. While NACI members are not government employees and remain external to the federal government, the secretariat supports committee meetings and deliberations, the rigorous scientific review of evidence and the development of NACI statements and communication products for health care providers and the public. The secretariat support is necessary as the committee members are volunteers, holding important full-time clinical and public health roles.
NACI complements the expertise of its broad membership by conducting extensive stakeholder engagement when developing its recommendations, involving many liaison organizations. The Canadian immunization committee, which is a federal, provincial and territorial table, is actively involved at multiple points in NACI's work. When drafting guidance on COVID-19 vaccines, including the AstraZeneca vaccine, NACI sought input from the special advisory committee on COVID-19, which is made up of provincial and territorial chief medical officers of health and other senior officials.
There is an important distinction to be made between NACI's role and Health Canada's function as Canada's national regulator. It is not uncommon for NACI to provide recommendations that are broader or narrower than the conditions of use approved by Health Canada. NACI is different from Health Canada, which does not dictate practice of medicine or make recommendations on how vaccines should be used in different age groups and subpopulations for public health impact.
In keeping with its mandate to optimize the public health benefits of immunization in Canada, NACI has historically provided preferential recommendations on the use of vaccines in key populations for diseases. Some examples include influenza and shingles vaccines. In making its recommendations, NACI also takes into consideration other vaccines available in Canada and may make preferential recommendations based on the current context. This is different from Health Canada as the regulatory authority that reviews each vaccine independently to assess if there is sufficient evidence of safety, efficacy and manufacturing quality to meet regulatory requirements for authorizations.
Clinicians are very used to consulting both the product monograph and NACI advice when making their clinical vaccine decisions for patients. They do not expect these to be identical, understanding that they are driven by different perspectives.
NACI's recommendations complement regulatory indications with real-world context and with information on public health strategies based on available and evolving evidence. The committee revises its recommendations when needed based on new evidence as well as the evolving context.
On the global stage, other countries rely on their respective national immunization technical advisory groups for COVID-19 expert advice. Through the NACI secretariat within PHAC, NACI is well connected to international advisory committees of this type. In fact, Canada is currently the chair of the global NITAG network, a World Health Organization-supported forum where national technical advisory committees on immunization share information and collaborate on work plans.
The NACI secretariat is in regular contact with countries bilaterally and through the global NITAG network to stay up to date on international COVID-19 developments.
PHAC expects different approaches to be adopted around the world in response to COVID-19. Every country develops immunization programs that are informed by local epidemiology, values, preferences, social infrastructure and health care systems. Naturally, these considerations vary significantly by country.
As you are all aware, real-world evidence on COVID-19 and vaccine effectiveness is evolving in real time. NACI continues to closely monitor and review this emerging evidence and will revise its recommendations as information becomes available.
I would like to thank the committee chair and members for the opportunity to address this committee.
Thank you very much, Mr. Chair.
At the start of every time I get a chance to speak at committee, I always thank the witnesses, but I have to tell you, I am so appreciative that we have experts and scientists like the people on this panel, the people at Health Canada and the people at NACI, who are making these decisions and these recommendations for provinces and territories, and not politicians. My gosh, what a state we'd be in. Thank you so very much for all that you are doing.
We talk about NACI, and we heard that they have been independent expert advice providers for over 50 years and have been appreciated by provinces and territories for 50 years. This is absolutely....
I want to go to Dr. Quach-Thanh.
When it comes to the health and safety of Canadians, we know that we need to rely, as I said, on experts in science. It's imperative that medical decisions be made by health professional experts, as I said, and not by politicians. Canadians need to know that the vaccines they are taking are safe and that the recommendations made for their use are based on what is best for them and what is best for Canadians across the country.
Dr. Quach-Thanh, can you talk just a little bit more about the role of the national advisory committee on immunization? Whom does NACI create their recommendations for, and what factors are you considering when making those recommendations?
Thank you for your question.
Basically, NACI creates the recommendations for provinces and territories so that each province and territory can then take up the recommendations and apply them to its own epidemiology, jurisdiction, logistics concerns, etc. Once our recommendations are out, they are then taken up, mashed up and put into the Canadian immunization guide, which is used by health care providers.
The problem with the pandemic is that everything changes so quickly that the CIG does not have a piece about COVID vaccine. Health care professionals are looking into the statements to try to understand the background to our recommendation. That piece is happening, but it's a little bit delayed, so we've decided that the statements would be used, at the same time, by health care professionals and provinces and territories.
NACI does not speak directly to Canadians, usually. We are there to support the public health measures. Having people go through it and try to understand it might be more complicated. We realize that the language we use is not layman's language. It is what public health understands and what health care providers understand. Even at that level, some health care providers called us to say they were not sure they understood the differences between strong NACI recommendations and discretionary, because this was based for provinces and territories.
The elements we look at to make a recommendation are burden of illness and vaccine characteristics, including safety, immunogenicity, efficacy and effectiveness, but also, as Kim said, ethics, equity, acceptability, feasibility, mathematical modelling and economics, when it comes to that. At this point in time, economics hasn't been incorporated in NACI vaccine decisions, because regardless of how much it costs, we are going to use those vaccines.
When we look at all of those elements, it is possible that a little bit less efficacy will be trumped by the ability to deliver more vaccines to more Canadians, because in our mathematical model, when you compare various possibilities and various scenarios, that seems to be the most optimal.
Are we always right? I can't say that we're 100% right. I mean, things are evolving. You make recommendations based on the best of your knowledge, and we really work at this from a generous and de bonne foi.... There's nothing here that we're trying to conceal; it just happens that this time around, we and Health Canada did not say the same thing.
As I said, it's not the first time it has happened. It's just the first time that people noticed.
I'll start with the last part of your question.
What changed since the original recommendation was that data came out of the U.K., Quebec and B.C. showing that at eight weeks we still had higher than 80% effectiveness, even in the long-term care residences, which to us was a sign that these vaccines are actually quite good.
As I said, given the mathematical modelling, what we did was decrease the vaccine effectiveness over time which...a more or less steeper curve to that decline. Regardless of the decline, giving one dose of vaccine to as many Canadians as possible was the scenario that most decreased the number of hospitalizations and deaths, mainly when you give it now because what's important is now. Maybe Nova Scotia is great, as you don't have that much transmission, but in other provinces it's rampant.
What we want is to decrease transmission as quickly as possible, because then you decrease the risk of having variants come up. A variant happens when the virus replicates and makes a mistake, and that mistake is actually good for it. If it replicates less, because it's transmitting less, then you decrease the risk of those variants occurring. Based on the data, we decided to extend the interval to allow for that first dose to be given to as many people as possible.
I think what is very important in all this is that we have surveillance systems for effectiveness so that we have real-time data of what's happening. In Quebec, B.C. and Alberta, and probably in Nova Scotia as well, people are able to say, “We're now at nine weeks and the vaccine effectiveness is X. We're still good to go. We're now at 10 weeks and the vaccine effectiveness is Y. We're still good to go.” When we see that it decreases anywhere, it's then easy to say, “We're rolling back the vaccines and starting to give that second dose now.”
All it means is that the vaccines are there, instead of decreasing in the people under 60, people with underlying medical conditions between 18 and 59. You bring back those vaccines and you say, “Those who were first vaccinated aged 70 and over, we're now giving it to them.”
We have the ability to follow a vaccine's effectiveness in time, and it is because of this that we're able to say.... We don't have all the data. I would be lying to you if I said we did, but we have the ability to change our recommendations quickly, and the provinces are doing that very well.
Thank you very much for the question about vaccine hesitancy. Obviously, it's a complex issue and there are many facets to it in terms of improving vaccine confidence in Canadians overall. There are multiple facets.
First of all, we have one of the most respected and most rigorous regulatory systems in the world with our colleagues at Health Canada. I think Canadians have assurance that any vaccine approved in Canada is both safe and effective. I think that's the first step.
Certainly, mass campaigns and the press conferences that many people, including me and Dr. Tam, are involved with are also important, in terms of reinforcing key messages to Canadians about the importance of vaccination and how it benefits them in terms of protection.
We also recognize—and I think this is a key point that maybe hasn't been raised—that Canadians, in terms of getting information to improve their comfort level with vaccines.... It's not because of me personally; I think it's because they have trust in their personal health care provider. One of the important things that we're also doing, through webinars and so on, is giving the tools so that frontline health care professionals and providers feel empowered and are able to give credible information so their patients can make an informed decision regarding getting vaccinated. I think that's a key step.
Another part is that we recognize there might be different levels of reticence or vaccine hesitancy in certain racialized communities. Therefore, it's also very important to engage with community leaders in those communities. We've seen them do that, for example, in various indigenous communities. The leaders have come forward, gotten vaccinated, put it on social media and said, “Look at this. I got my vaccine. I'm protected. My family is protected. It's good for me. It's good for everyone.” Those are the kinds of things we're doing.
I would also say that, at the end of the day, there is a bit of a responsibility on every Canadian. The fact is that the Internet is a powerful tool and there's a lot of misinformation, disinformation and so on. The responsible use of the Internet, in terms of not using clickbait and making misinformation go viral, is also very important.
Finally, I want to say that—
I think Ms. Rempel Garner asked a key question. Canadians want to know, is this a good vaccine? Should I recommend it for my parents, if they have the opportunity to get this vaccine, or for my brother, who has a lot of underlying medical problems? I think the answer is yes. Unfortunately, in this meeting it's about as clear as mud, as far as I'm concerned, because there are so many different numbers out there. I think part of the confusion is the difference between “efficiency” and “effectiveness”.
I'll direct this to you, Dr. Quach-Thanh, because I think you know the numbers pretty well. My understanding of the efficiency comes from the phase three randomized control trial, where you had either the AstraZeneca vaccine or the placebo. Overall, the efficacy was 62%, but it was something like 40% in people over 65. However, to my understanding, I think in North America it showed 72% efficiency, and with half the first dose 90% efficiency.
That's from a randomized control trial, where you pre-select the people. In the actual real-world experience, the effectiveness has actually shown AstraZeneca looking better. There was the study by Hung and Poland in The Lancet, with 17,000 people. This was the one where they looked at giving the booster four months afterwards. They found an 81% effectiveness, including in the elderly. The other numbers I saw showed, with a four-month interval in spacing, 76% to 82%. They were certainly a lot better numbers than the 62% and the 40%. If you look at the efficiency or efficacy from the actual trial with AstraZeneca in preventing deaths, it was 100% efficient or effective in preventing death. In hospitalizations, the Scottish study showed 94%, but you're not going by those numbers.
Is that about right? In the actual study by AstraZeneca, nobody who got the vaccine died, and giving it four months apart was about 80% effective in preventing clinical illness. Is that right? As well, what is the hospitalization rate?
I will try to answer your question. I'm not convinced that I fully understood it.
In terms of asymptomatic infections, that data is being collected in various studies. We know that, for AstraZeneca, which looked at this factor when the other companies did not—we will at least give them that—the efficacy from the standpoint of decreasing asymptomatic infections was not good. The other companies did not study this factor, so that may be the case for them as well.
In terms of variants, no link has been established between an asymptomatic infection and a variant. Currently, several ways are being used to find out if a vaccine works against a variant or not. We have in vitro methods. After vaccinating a person, we take their antibodies to see if they are able to neutralize the variant virus. In addition, we look to see if the person's cellular immunity has any effect on the variant.
The other way is to do vaccine effectiveness studies. They involve determining how many infections the vaccine is able to prevent from a variant, compared to when there is no variant.
In their phase 3 studies, AstraZeneca and Johnson & Johnson struggled with the South African and United Kingdom variants. So they sometimes have somewhat lower vaccine efficacy rates than Pfizer and Moderna, who did their studies much earlier, before the variants emerged. You have to take that into account in the data analysis as well.
As to how the current data can be used to determine whether or not we're able to control the variants, it's really possible by monitoring vaccine effectiveness in the population.