Covid Vaccines Explained

Christina Kingan ’23
EE Staff Writer

Hope is in the air with a new year, and our normal lives potentially just around the corner. The long-awaited COVID-19 vaccine is finally becoming available to the public. After many trial and error processes, the CDC has approved four different ways of fighting the virus, all of them aiming to prepare the immune system to be able to fight off the virus if ever exposed to it. Each works in its own specific way according to the Vaccine Alliance organization, Gavi.

The first type is the whole-virus vaccine. This type of vaccine weakens the virus and makes it nonpathogenic (inactive). When the inactive virus enters the body, it stimulates an immune response without causing disease to the body. When the body’s immune system reaches the virus, it will attack it with antibodies and T cells. The purpose of this is to allow memory cells to remember the virus and be able to know what cells to produce to target the virus more efficiently the next time the body encounters it. 

The second type is the protein subunit vaccine. This method takes the spike proteins of the virus and introduces them to the body. Like the previous method, this type of vaccine is also incapable of causing disease.

The benefit of this vaccine is that it is cheaper and easier to make. The disadvantage is that since the fragments cannot infect host cells and are less threatening, the immune system may not recognize them as attacking cells. The problem with this is that they will prompt a weaker immune response. To prevent this from being the case, vaccines of this type will usually include chemical agents known as adjuvants, which will trigger a more robust response from the body. Another alternative is the administration of booster shots, which are extra doses of the vaccine to boost the immune system even more. 

Where these vaccines rely on exposing the body to the virus by putting the antigens inside, other vaccines have been developed that allow for the body to learn to fight off the virus by using their own cells. By controlling the cell mechanisms, these vaccines have the ability to copy the way the virus usually reproduces during what would be an actual infection. As opposed to producing copies of the virus, the cells will only produce large quantities of antigen, which will trigger strong immune responses.

The two types of vaccines that go this route are viral vector vaccines and mRNA vaccines. In both cases, they aim to take fragments of genetic code taken from the target virus to put into the patients’ cells.

Specifically for Covid, the strand SARS-CoV-2 is inserted into the patient’s cells. The mRNA vaccines are direct. They attach the virus’s code to another molecule for the molecule to bring the code into the cell, or the code can be pushed into the cell by using a gene gun. The vaccines are cheap and relatively easy to develop, so that is an advantage, but with everything, it is still new technology.

The viral vector vaccine also takes the genetic code of the antigen, but instead of just putting it into the patient’s cells, it will be delivered utilizing a harmless virus that acts as a vessel. It delivers the code into the cells rather than the code being directly inserted like in the mRNA vaccine process. These can be a little harder to develop, but they trigger strong immune responses without the need for additional adjuvants. The appealing side of this method is that vectors could support various antigens, which, in theory, can speed up the development of the vaccine. 

According to Mark Terry of, there are currently three vaccines in phase three clinical trials. AstraZeneca’s COVID-19 vaccine is one of the three. This vaccine is a viral vector type. As previously explained, they take a harmless virus and insert the genetic code of the virus into it so that it can be delivered to the patient’s cells. In this case, the harmless virus that is being used is the replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus that causes infections in chimpanzees.

The second large-scale vaccine that is doing well is Janssen’s COVID-19 vaccine. This vaccine is also a type of vector vaccine. Like the other vaccine, this one uses a modified adenovirus cell to carry the SARS-CoV-2 to mimic the spike proteins, and as already explained, to bring the gene to the patient’s cells. The virus was modified to make sure it could not replicate, and it became a harmless vessel. 

The third vaccine is called Novavax’s COVID-19 vaccine. This is a protein subunit vaccine. It takes spike proteins (harvested by inserting the Covid gene into a virus called baculovirus; which infected moth cells and allowed for them to build spike proteins and form spikes which replicated the ones of the coronavirus without it being able to cause the disease) and injects them into the arm muscles. The vaccine consists of spike nanoparticles and a compound from the soapbark tree, which is only there because it attracts immune cells. With more immune cells attracted to the site, the stronger the response will be to the nanoparticles, allowing the body to build up the antibodies so it will be prepared for future exposure to the virus. 

A major concern of the vaccination process is that very few people seem to know when they will actually be able to receive one. The CDC has implemented a phase one plan with three parts. The first part is offered to healthcare personnel and residents of long-term care facilities. After this part has been completed, the second segment includes the frontline essential workers (which represents firefighters, police officers, agriculture workers, postal service workers, teachers, grocery store workers, public transit workers, and more). Part b also provides the vaccine to people 75 years and older.

The third part, part c, is directed towards people of 65-74 years old, 16-64 who have underlying medical conditions, and the rest of the essential workers (transportation, food service, communications, law, media, public safety, housing construction and finance, public health, and more).

Some people may fear that their allergies may cause them to react to the vaccine; however, doctors advise them to get the vaccine still. People with allergies to food, pollen, latex, even penicillin and certain types of medicines, are not at risk of a reaction. There is only one exception, people who in the past have had an anaphylactic reaction to a vaccine should not get the shot.

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