CPHO关于COVID-19的声明系列:mRNA疫苗

来自:加拿大公共卫生署

声明

2021年1月10日| 渥太华| 加拿大公共卫生署

加拿大首席公共卫生官谭丽珊博士今天发表以下声明:

2020年底标志着加拿大对抗COVID-19的转折点。我们目睹了加拿大批准了COVID-19的前两种疫苗-辉瑞-BioNTech疫苗和Moderna疫苗,并在全国范围内推广了这些疫苗的初始剂量。知道第一批加拿大人已经接种了COVID-19疫苗,这给我们带来了一些积极的信息,使我们可以在困难的一年结束时集中精力,并继续为来年加油我们的希望,力量和决心。

现在,在2021年初,这些新近批准的疫苗成为许多加拿大人的头等大事,并且对了解更多有关它们的兴趣浓厚。辉瑞BioNTech疫苗和Moderna疫苗都是mRNA疫苗。对于许多加拿大人来说,这可能是您第一次听说这种类型的疫苗,可以理解您可能会有疑问。那么什么是mRNA疫苗?重要的是,它们是否起作用并且安全吗?

今天的声明旨在通过提供我们目前拥有的最新信息来回答这些重要问题。随着新证据的出现,我们将更详细地探讨其中一些问题。

疫苗的工作方式

让我们从疫苗如何运作的基础开始。简而言之,疫苗有助于增强您对疾病的免疫力并保护您免受疾病侵扰。它们会训练您的免疫系统,以识别引起疾病的病原体(例如病毒)何时进入您的体内,以便您的免疫系统准备好对它们进行防御(如果您以后再暴露出来)。这种防御或免疫反应包括产生特殊蛋白质,称为抗体,有助于破坏病原体。将来,如果您暴露于相同的病原体,您的免疫系统会记住该病原体并消灭它,然后才能生病。

mRNA疫苗

mRNA疫苗在特殊涂层中包含遗传物质链-mRNA。这种特殊的涂层可保护mRNA不受体内酶的破坏。mRNA为您的体内细胞提供了一个“指令集”,使蛋白质看起来像冠状病毒外部散布的“穗状蛋白质”。您的免疫系统将这些蛋白质识别为通常在您体内不存在的蛋白质,并通过制造抗体开始对其产生免疫反应。一旦产生蛋白质,mRNA就会分解并从细胞中清除。

mRNA疫苗以数十年来的科学进步为基础,包括了解mRNA结构以及确定病毒基因序列的技术进步。mRNA疫苗技术的最新进展集中在mRNA本身的本质所面临的挑战上-它非常脆弱,很容易在细胞外分解。研究人员发现,将mRNA包裹在称为脂质纳米颗粒的微小脂肪类微小胶囊中,有助于保护mRNA不受血液中酶的破坏,并可以安全地传递至细胞。尽管这项创新有助于防止mRNA在您的体内被过快破坏,

COVID-19 mRNA疫苗开发和法规审查

对于COVID-19,通过快速解码和共享SARS-CoV-2遗传密码(导致COVID-19的病毒)来促进mRNA疫苗的开发,该病毒于2020年1月在线发表。这使世界各地的科学家得以开始设计针对COVID-19的mRNA疫苗。几周之内,疫苗就可以在动物模型中进行测试了,并将于2020年3月进行人体临床试验。

加拿大卫生部分别于10月9日和13日收到了辉瑞BioNTech和Moderna疫苗申请,以允许在加拿大使用。加拿大卫生部收到的每份疫苗都经过审核,以确保该疫苗安全,有效和高质量,并且其收益超过潜在风险。此外,加拿大卫生部确保疫苗的生产均遵循既定的高质量国际标准(良好的生产规范)。

加拿大卫生部和加拿大公共卫生局还审查了制造商将如何进行安全监控,以最大程度地减少已发现的风险。要求制造商在疫苗推出后继续向加拿大卫生部提供有关疫苗的安全性,功效和质量的信息。辉瑞公司和BioNTech公司以及Moderna公司将在接受每种疫苗的第二剂疫苗后至少两年跟踪临床试验参与者。有关这些疫苗的法规批准的其他信息,您可以访问COVID-19疫苗和治疗门户。

副作用或不良反应

正如我们在先前的声明中所指出的,接种疫苗后会出现一些轻度到中度的副作用(也称为不良反应),这很常见,包括注射部位的疼痛,疲劳,头痛,发冷,发烧以及关节和关节疼痛。肌肉疼痛。这些作用是短暂的,随着免疫系统被激活,反映出您身体的自然反应。加拿大卫生部和加拿大公共卫生局将与各省和地区,国际合作伙伴以及制造商合作,通过许多系统监视疫苗的安全性,并警告加拿大人任何可能引起关注的副作用。

维持公共卫生措施并寻求可靠的信息来源

随着疫苗在全国各地的普及以及加拿大和全球医学,公共卫生和研究界继续积极监测这些菌株的出现和影响,保持警惕比以往任何时候更为重要。这意味着要遵守所有公共卫生措施-保持身体距离,经常洗手,戴口罩以及即使在症状轻微的情况下也要待在家里。此外,尽管已显示出辉瑞-BioNTech和Moderna疫苗在预防COVID-19疾病和严重后果方面非常有效,但仍在研究它们如何有效预防已接种疫苗的人传播病毒给别人。

这也是非常重要的,加拿大人继续确保他们使用的是信任可靠的来源,当他们寻找关于COVID-19的信息,包括有关基因疫苗。在线上散布着许多错误信息,这些信息很容易混淆或误导加拿大人。有关COVID-19的其他可信信息,加拿大政府网站Canada.ca/coronavirus是一个不错的起点。您还可以在省级和地方卫生机构的网站上以及世界卫生组织和红十字会等国际机构中找到可靠的信息。

回顾2020年,就我们对COVID-19的了解以及在加拿大和国际上前所未有的合作与创新(这是COVID-19响应的特点)而言,我们所取得的成就令人难以置信。尽管我知道对每个人来说都是充满挑战的一年,但加拿大人的集体力量和韧性给我留下了深刻的印象。这有助于激励我,反过来,在我们共同探索2021年的过程中,我将努力为您提供与事实和基于证据的健康相关的信息。

CPHO Issue Statement Series on COVID-19: mRNA Vaccines 

From: Public Health Agency of Canada

Statement

January 10, 2021 | Ottawa, ON | Public Health Agency of Canada

Dr. Theresa Tam, Canada’s Chief Public Health Officer, issued the following statement today:

The end of 2020 marked a turning point for Canada in our fight against COVID-19. We witnessed Canadian approval of the first two vaccines for COVID-19 – the Pfizer-BioNTech vaccine and the Moderna vaccine, and rollout of initial doses of these vaccines across the country. Knowing the first Canadians had been vaccinated against COVID-19 gave us something positive to focus on at the end of a difficult year, and continues to fuel our hope, strength, and resolve for the year ahead.

Now, at the beginning of 2021, these recently approved vaccines are top of mind for many Canadians, and there is a keen interest in learning more about them. The Pfizer-BioNTech and the Moderna vaccines are both mRNA vaccines. For many Canadians, this may be the first time you have heard about this type of vaccine and it is understandable that you may have questions. So what are mRNA vaccines? And importantly, do they work and are they safe?

Today’s statement aims to answer these important questions by providing the latest information we have at this time. We will be exploring some of these issues in greater detail, as new evidence emerges.

How Vaccines Work

Let’s start with the basics of how vaccines work. In a nutshell, vaccines help build up your immunity to a disease and protect you from getting sick. They train your immune system to recognize when disease-causing pathogens, such as viruses, enter your body so that your immune system is ready to mount a defense against them, if you are exposed at a later time. This defense, or immune response, includes the production of special proteins called antibodies that help to destroy the pathogen. In the future, if you are exposed to the same pathogen, your immune system will remember the pathogen and destroy it before it can make you sick.

mRNA Vaccines

mRNA vaccines contain strands of genetic material – the mRNA – inside a special coating. This special coating protects the mRNA from being broken down by enzymes in your body. The mRNA delivers an “instruction set” to the cells in your body to make proteins that look like the “spike proteins” studded on the outside of the coronavirus. Your immune system identifies these proteins as ones that are not usually found in your body and begins building an immune response to them by making antibodies. Once the proteins are produced, the mRNA breaks down and is cleared from your cells.

mRNA vaccines build on scientific advancements made over several decades, including understanding the structure of mRNA, and advancements in technology to determine the genetic sequences of viruses. More recent progress on mRNA vaccine technologies has focused on a challenge that lies in the nature of mRNA itself – it is very fragile and breaks down very easily outside of a cell. Researchers have discovered that enclosing mRNA in microscopically small capsules of a fat-like substance, called lipid nanoparticles, helps to protect the mRNA from being broken down by enzymes in your blood and allows it to be delivered safely to your cells. While this innovation helps to prevent the mRNA from being destroyed too quickly in your body, it means that these vaccines need to be shipped and stored at low and ultra-low temperatures to preserve their special formulation.

COVID-19 mRNA Vaccine Development and Regulatory Review

For COVID-19, developing an mRNA vaccine was facilitated by rapid decoding and sharing of the SARS-CoV-2 genetic code, the virus that causes COVID-19, which was published online in January 2020. This allowed scientists around the world to begin designing mRNA vaccines against COVID-19. Within weeks, vaccines were ready to test in animal models, with human clinical trials following in March 2020.

Health Canada received Pfizer-BioNTech and Moderna vaccine applications to permit use in Canada on October 9th and 13th, respectively. Every vaccine submission that Health Canada receives is reviewed to ensure that the vaccine is safe, effective, and of high quality, and that its benefits outweigh potential risks. In addition, Health Canada makes sure that the vaccines are manufactured according to established high quality international standards (good manufacturing practices).

Health Canada and the Public Health Agency of Canada also review how the manufacturer will undertake safety monitoring to minimize any identified risks. Manufacturers are required to continue providing information to Health Canada on the safety, efficacy and quality of the vaccine following vaccine roll out. Pfizer and BioNTech, as well as Moderna, will be following clinical trial participants for at least two years after receiving the second dose of each respective vaccine. For additional information on the regulatory approval of these vaccines, you can visit the COVID-19 vaccines and treatments portal.

Side Effects or Adverse Reactions

As we noted in a previous statement, it is quite common to experience some mild to moderate side effects (also known as adverse reactions) after receiving a vaccine, including pain at the injection site, fatigue, headache, chills, fever, and joint and muscle pain. These effects are transient and reflect your body’s natural response as the immune system gets activated. Health Canada and the Public Health Agency of Canada, in collaboration with the provinces and territories, international partners, and the manufacturer, will be monitoring vaccine safety through a number of systems and will warn Canadians about any potential side effects of concern.

Maintaining Public Health Measures and Seeking Credible Sources of Information

As vaccines roll out across the country and as the Canadian and global medical, public health and research communities continue to actively monitor the emergence and impact of these strains, it is more crucial than ever to remain vigilant. This means keeping up with all public health measures – maintaining physical distance, washing your hands frequently, wearing a mask, and staying home, even if you have mild symptoms. In addition, while the Pfizer-BioNTech and Moderna vaccines have been shown to be highly effective at preventing COVID-19 illness and serious outcomes, research is still ongoing into how effective they may be at preventing transmission of the virus from people who have been vaccinated to others.

It is also very important that Canadians continue to ensure that they are using trusted and credible sources when they seek information about COVID-19, including that relating to mRNA vaccines. There is a lot of misinformation circulating online, which can easily confuse or mislead Canadians. For additional trustworthy information about COVID-19, the Government of Canada website, Canada.ca/coronavirus, is a good place to start. You can also find reliable information on your provincial and local health agency website, as well as from international agencies like the World Health Organization and the Red Cross.

Looking back at 2020, it is incredible to reflect on how far we have come in terms of our knowledge of COVID-19, as well as the unprecedented collaboration and innovation, both in Canada and internationally, that has characterized the COVID-19 response. While I know it was an extremely challenging year for everyone, I was consistently impressed by Canadians’ collective strength and resilience. It has helped to motivate me and in turn, I will strive to provide you with factual and evidence-based health-related information as we navigate 2021 together.


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