top of page


Lulu Morse

In December, the United States Food and Drug Administration (FDA) gave emergency use authorizations for the Pfizer/BioNTech COVID-19 vaccine and the Moderna COVID-19 vaccine. Globally, there are nine vaccines that have been approved by various countries. There are also several vaccines in development and earlier clinical trials.  

How the Vaccine Works

Vaccines work by training the human body’s immune system to recognize and fight off viruses and bacteria. This way, if the person is exposed to a virus or bacteria that can cause disease, their body's natural defenses can destroy it and prevent illness. Even if you have had COVID-19 in the past, doctors say you should still get vaccinated since reinfection can happen, and your body’s immunity to COVID-19 is unknown. It is not known how long antibodies will protect you or how high your antibody levels need to be to offer you protection; false positives are also possible on antibody tests. There are currently three types of COVID-19 vaccines being researched: mRNA, Protein Subunit, and Vector vaccines. 

The Moderna and Pfizer COVID-19 vaccines are mRNA vaccines. mRNA vaccines have material from the COVID-19 virus that gives our cells instructions for making a harmless protein that is unique to the virus. After the cell copies the protein, they destroy the vaccines’ genetic material. The cells recognize that the copied protein should not be there, so the cells “build T-lymphocytes and B-lymphocytes that will remember how to fight the virus.” 

Protein Subunit vaccines include proteins of the COVID-19 virus, and the body makes T-lymphocytes and antibodies. Thus, if a person who got this vaccine is infected with COVID-19, their memory cells will remember and fight the virus. 

The Vector Vaccines contain weakened versions of a live COVID-19 virus, called vectors. Inside human cells, vectors give genetic material to cells. The genetic material contains instructions that cells can use to make a protein that is unique to the virus that causes COVID-19. Cells then copy the protein and build T-lymphocytes and B-lymphocytes to fight the virus in the future. 

People should continue to wear a mask and social distance even after getting the vaccine. A person can still get COVID-19 after receiving the vaccine, and some people have already, including 75-year-old Representative Coleman, 85-year-old Colin Horseman, a 45-year-old emergency nurse known only as Matthew W, and others. However, this does not mean that the vaccine is ineffective or useless. There are many ways one can be infected after a vaccine. Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine in Tennessee, said, “Some people were unknowingly infected before they received their first dose.” The protection from the first dose of the Pfizer vaccine does not start until approximately 12 days, and then it is 52 percent effective. The Moderna vaccine and Pfizer vaccine require two doses, and after the second dose, the vaccines are about 95 percent effective.

The vaccine works to keep a person from getting seriously ill, but if someone with the vaccine gets infected, they may still be able to spread the virus. According to Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security in Maryland, there is still an open question as to whether or not the vaccine can prevent an asymptomatic COVID-19 infection. 

“The end game is to stop death, to stop hospitals from going into crisis, and all of these vaccines, even including against the South African variant, seem to do that substantially,” said Dr. Adalja. Thus, despite any drawbacks, the vaccine still is a significant step in relieving the effects of COVID-19. The COVID-19 relief effort will be especially effective if people continue to wear masks and social distance. 

The New COVID-19 Variants and the Vaccine

Since the vaccines’ approval, there have been new strains found in various parts of the world that have raised concerns for the vaccines’ effectiveness on these new strains. Officials found new variants of COVID-19 in England, South Africa, Brazil, California, and other areas. The U.K. strain, known as B.1.1.7,  is more infectious because of changes in the spike protein that make it stickier and bind tighter to our cells. The U.K. government has also reported the variant likely has a higher mortality rate. The South African strain, known as B.1.351, has exhibited a worrisome dominance in South Africa. The mutations “make it about 50 percent easier to catch,” but it has not yet proven to be more lethal than others. More than 90 percent of the cases sequenced in South Africa were the new variant. Many people who had contracted the earlier form of the virus are being infected with the new one, especially if they originally had mild cases or low antibody counts. 

Mutations of COVID-19 are not a new phenomenon and will not likely stop. In 2020 several mutations caught researchers’ attention, but ultimately they had no significant differences in coronavirus behavior. “New variants of the SARS-CoV-2 virus are detected every week,” says Dr. Ray of John Hopkins Medicine. However, the new strains detected have undergone similar changes to their spike proteins independently while geographically distanced, which has raised concerns for scientists and the vaccines’ effectiveness.

Dr. Ray says, “There is new evidence from laboratory studies that some immune responses driven by current vaccines could be less effective against some of the new strains." It is probable the mutations “allow the coronaviruses to escape the antibodies in currently available therapies and those induced by vaccines.” However, more data is needed to investigate this possibility. 

Pfizer says their vaccine works against the U.K. variant as it does to the earlier forms of COVID-19. Pfizer and BioNTech also published studies showing their vaccine is only slightly less effective against the South African variant, but these findings only examined 2 of the variants’ 23 mutations. Pfizer's chief executive, Albert Bourla, said that “Pfizer is considering whether its vaccine needs to be altered to protect against the South African variant.”

Moderna announced that their two-dose regimen of the Moderna COVID-19 Vaccine is “expected to be protective against emerging strains detected to date.” According to the Washington Post, Moderna is also “developing a new booster shot and testing out a three-shot regimen” to increase its protection for the South African variant since the antibodies its vaccine creates were less effective at neutralizing this variant than previously dominant variants. 

 Novavax, a vaccine in the third and final phase of its testing stage, has done more extensive testing on the new variant. Their vaccine is 95.6% effective against the original COVID-19 strain and 85.6% effective against the U.K. variant strain. However, their vaccine was less than 50% effective against the South African Variant.

The future of vaccines is still unknown. John Hopkins Medicine reports that “as long as the coronavirus spreads through the population, mutations will continue to happen'' which could affect the vaccine in the future. Pfizer’s chief executive, Albert Bourla, said there was “a high possibility” that the new strains could eventually mean the firm’s vaccine was redundant; this is not yet the case, but there is “a very high likelihood that one day that will happen.” As new variants generate, more research will be required to determine the vaccine’s effectiveness in the future.

As scientists find new strains, people must continue to wear masks and social distance, even with the vaccine. More variants can develop, and research on the vaccine’s effectiveness cannot outrun the speed at which new strains can spread.


Bader M.D, Thomas. “Recovered from COVID-19? Why You Still Need a Vaccine.” Hackensack Meridian Health, 20 January 2021.

Blackall, Molly. “Two new Covid vaccines have less efficacy against South African strain.” The Guardian, 30 January 2021.

Centers for Disease Control and Prevention. “How Vaccines Work.” 2021. Accessed 13 January 2021.

Craven, Jeff. “COVID-19 Vaccine Tracker.” Regulatory Affairs Professionals Society, 29 January 2021.

Novavax. “Novavax COVID-19 Vaccine Demonstrates 89.3% Efficacy in U.K. Phase 3 Trial.” Novavax, 2021. Accessed 28 January 2021.

Plater, Roz. “You Can Still Spread, Develop COVID-19 After Getting a Vaccine: What to Know.” Healthline, 19 January 2021.

Polack M.D., Ferbabdo P., et al. “Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.” The New England Journal of Medicine, no. 383, 2020, pp. 2603-2615.

Ray, Stuart, et al. “New Variants of Coronavirus: What You Should Know.” John Hopkins Medicine, Updated 29 January 2021.

Rossi, Mellissa, and Laura Ramirez. “More contagious U.K. COVID strain is also deadlier, Boris Johnson warns.” Yahoo! News, 22 January 2021.

Tapp, Tom. “L.A. And CA Flying Blind On New Covid-19 Mutants; Fauci Calls Virus Variants “A Wake-Up Call.” Deadline, 29 January 2021.

Wroughton, Lesley, and Max Bearak. “Coronavirus variant sweeps South Africa, exhibiting ‘terrifying’ dominance.” The Washington Post, 28 January 2021.

Just About Everything You Need to Know About the COVID-19 Vaccine: Academics
bottom of page