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How does the COVID-19 vaccine work? How does it differ from the flu vaccine? Is it safe?

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Today the first person in the United States received a COVID-19 vaccination, a vaccine intended to prevent the coronavirus infection. This vaccine is a light at the end of the tunnel, a hope that the pandemic can be stopped. It’s practically a miracle that it was developed so fast.

Typically, vaccines take years to develop. In fact, the quickest any vaccine was developed was 4 years (mumps, 1967). The COVID-19 vaccine was developed in less than a year. How did scientists create the vaccine in record time?

How a normal flu vaccine is developed

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Vaccines, like the one you get for the flu, inject lifeless (inactivated) virus particles into the body. These particles trick the body into thinking it’s being infected by the real virus. The body reacts to the virus by producing antibodies that protect against infection. Once the body learns how to recognize and destroy a virus, it remembers how to fight off viruses like it in the future.

The process to develop a vaccine takes a long time. The vaccine first has to be designed. Scientists have to choose which viruses will be used to create the vaccine. Then it has to be developed. Finally, manufacturers have to make the vaccine. They do this by growing the virus on cell cultures which takes a long time.

A novel idea – using mRNA in vaccines

The COVID-19 vaccine is different from a normal flu vaccine. In fact, it’s the first widespread vaccine of its kind. Rather than injecting inactivated virus particles into the body, the COVID-19 vaccine uses messenger RNA to trick cells into making antibodies.

Messenger ribonucleic acid, or mRNA, carries genetic code from a cell’s nucleus to ribosomes, the cell’s protein making machinery. This is important because proteins are what vaccines seek to create. In the case of the COVID-19 vaccine, the goal is to create a spiked protein that looks enough like the COVID-19 spiked virus to make the body think it’s the real thing.

The body’s natural process for creating a protein begins with DNA. DNA acts like the map that cells use to create a protein. DNA communicates the instructions to the cell using mRNA. mRNA travels from the nucleus of the cell to the part of the cell known as the cytoplasm, which houses ribosomes. Ribosomes are complex machinery in the cells that are responsible for making proteins. Then, through another process known as translation, ribosomes ‘read’ the mRNA, and follow the instructions, creating the protein step by step. The cell then expresses the protein and it, in turn, carries out its designated function in the cell or the body.

How the COVID-19 vaccine was developed

Long Island nurse Sandra Lindsay is the first person in the United States to receive the Pfizer-BioNTech COVID-19 vaccine.

Very early on in the coronavirus pandemic, the genetic sequence of the virus was mapped out and sent to scientists all over the world. Scientists wanted to create the same sequence in mRNA and deliver it to the body’s cells so that once inside the cell, ribosomes would read the code, build the spiked protein and send the protein throughout the body, triggering the creation of antibodies to fight off what the body thinks is a real virus.

The mRNA that scientists created in the lab works just like the mRNA created by your body’s cells. The lab-created mRNA instructs cells to make a harmless version of the spike protein that is wrapped around the coronavirus. The defanged spike proteins prompt a person’s immune system to produce antibodies that could fight off the real virus.

Why the COVID-19 mRNA method is quicker to develop

Creating mRNA vaccines is much quicker than the older method of growing dead virus particles in a cell culture. To create the COVID-19 mRNA vaccine, scientists merely plugged the genetic code for the coronavirus spiked protein into their software to create the mRNA sequence. Then the mRNA is placed in machines that deposit the vaccine in the fatty envelope that carries it to a cellular target. It only takes about a week to make a batch of doses using this method. The time to market for mRNA vaccines is much faster than the older methods.

The disadvantage of mRNA vaccines

Vaccines are similar to dairy or meat products in that their chemical structures are maintained when they are kept within certain temperature ranges. Drug companies have lots of data on optimal temperatures for vaccines such as chickenpox and shingles. The COVID-19 vaccine is no different – except it must be stored at very, very low temperatures.

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Unlike DNA which survives for generations, RNA is a more temporary structure. Once it carries a message, its job is done, and it quickly degrades. The mRNA in the Covid-19 vaccine is believed to suffer the same fate. Thus, the final vaccine must be stored at subzero temperatures to stay stable. This requires liquid nitrogen or dry ice which makes it more difficult to transport and store. In fact, many hospitals do not have freezers capable of creating temperatures that low.

The other disadvantage of the mRNA vaccine is its short shelf life. Even when stored at ultracold temperatures, the Covid-19 vaccine must be used within months before it begins to lose it effectiveness.

Is the COVID-19 vaccine safe?

The COVID-19 vaccine is new technology, little used, but very important to the welfare of the country. The COVID-19 vaccine went through various approval processes but after being rushed to market in record time, many fear the vaccine may not be safe.

The vaccine was tested on about 40,000 people before being approved. Many fell ill but only 8 out of the 40,000 people developed severe symptoms. For a reason that is not yet known, they developed appendicitis. Nobody died from the vaccine, but the development of appendicitis was a concern.

Hospitals that distribute the virus are required to report results back to the drug company. They must report any glitches, mistakes, or problems they see patients develop. Scientists are confident the vaccine is safe but the more it is distributed, the more we’ll learn about it.

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