Covid-19 Vaccines: What You Need to Know

Written by Dr. Ryner Lai
June 21, 2021

The Covid-19 pandemic has wrecked lives and livelihoods, and last year in 2020, pharmaceutical companies all across the globe have been racing to produce vaccines that can save lives and halt the spread of the virus. The world now has a few leading Covid-19 vaccines that have been approved by various governmental bodies. 


The United States has an ambitious target of getting most of its population vaccinated by the summer of 2021 (provided that they want to be). Studies have shown that vaccines are effective in reducing severe illnesses caused by Covid-19, which should relieve the burden on healthcare facilities and facilitate the return to life as normal. 


How Vaccines Work 

To understand how vaccines work, it is important to first understand how our body’s immune system works. When our bodies detect a foreign intruder, such as a virus or bacteria, the immune system kicks in to defeat the intruder. It does this by deploying immune cells to fight the infection. 


Once the infection has been defeated, the immune cells retain “memory” on how to fight the infection. This means that if our bodies encounter the same infection, the immune cells are able to “remember” how to fight the infection and defeat it much more quickly and effectively. 


Vaccines take advantage of the ability of our bodies to produce “memory” immune cells to fight against infection. Vaccines typically work by either introducing an inactivated form of the virus or subunits of the virus in order to trigger the body to mount an initial immune response. Once the immune response has been triggered, “memory” immune cells are produced, which can be used to fight against the actual virus if the body ever encounters it. 


Vaccines are an effective and safe method to fight against diseases. They also undergo a rigorous testing and research process to ensure that they are safe before they are released to the public. It is thanks to vaccines that diseases like polio, measles, and smallpox are no longer public health threats and it is because of vaccines that our life expectancy now is significantly longer than it used to be.


Types of Vaccines 

There are many types of vaccines that are available across the globe. For example, China has developed a vaccine known as Sinovac, and Russia has a vaccine known as Sputnik V. However, at the time of writing, these vaccines do not have approval for use in the United States yet. There are, however, 3 vaccines that currently have the approval to be used in the United States. Let’s have a look at them: 

Pfizer-BioNTech Vaccine 

This vaccine was created through the partnership of Pfizer and BioNTech and is an mRNA vaccine. It works in a way that is unconventional for traditional vaccines; while traditional vaccines use a weak or inactivated virus to trigger the body’s immune response, mRNA vaccines work by teaching the body to produce a protein that can trigger an immune response. This immune response then causes “memory” immune cells to form, which helps the body to mount a more effective immune response should it come into contact with the actual virus. 


Clinical research has found that this vaccine is 95% effective in preventing Covid-19 illness. This vaccine is administered in 2 doses, 21 days apart. The doses are administered through a shot in the muscle of the upper arm (and not through a vein, which is more painful). 


Moderna Vaccine 

The Moderna vaccine is also an mRNA vaccine, meaning that it works in a similar way to the Pfizer/BioNTech vaccine as described above. Clinical studies have demonstrated that it is 94.1% effective at preventing Covid-19 illness. It is administered with 2 shots, 28 days (one month) apart. The Moderna vaccine is also administered through a shot in the muscle of the upper arm. 


Johnson & Johnson’s Janssen Vaccine 

The Johnson & Johnson vaccine is a viral vector vaccine. This means that it uses a modified version of the virus to trigger an immune response in the body. It is important to note that the vector is not the virus itself and hence you cannot get the virus from the vaccine. 


Clinical research has shown that it is 66.3% effective in preventing Covid-19 illness. Unlike the Pfizer/BioNTech vaccines and the Moderna vaccine, this vaccine only requires 1 shot in the muscle of the upper arm. It has also been more thoroughly tested in populations that include some of the mutated Covid-19 variants which we see more and more of. And finally, it can be transported more easily than the other two vaccines (in refrigerated temperatures vs freezing temperatures). 


Should You Get Vaccinated? 

Vaccines that have been approved for public use must have gone through rigorous tests and checks to ensure that they are indeed safe. Taking a vaccine is about protecting yourself, but more than that, it is also about protecting the people around you and your loved ones. When a high enough percentage of the population has been vaccinated, a situation known as herd immunity is created. Herd immunity is a situation in which even people who are not vaccinated are protected from a particular disease because enough people in the community are immune to it and hence do not pass it onto others. 


Taking a vaccine usually produces mild side effects, which may include nausea, headache, muscle pain, and fever, but these side effects usually last for only a day or two. 


To stay up to date with the latest information about the Covid-19 vaccination program, please visit the Centers for Disease Control and Prevention (CDC)’s vaccine information page. 


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