COVID-19 vaccines: a scientific explanation

December 6th, 2020. By Ethan Tam '22

As new COVID-19 vaccines emerge this month, conspiracy theories plague the internet, reinforcing beliefs of anti-vaxxers. This article delves into the molecular level of how vaccines function to explain the potential of the Moderna and Pfizer vaccines.

As the U.S. enters into December, new hope emerges with the introduction of the Moderna and Pfizer vaccines, the first potential key scientific breakthroughs to combat COVID-19. These are new vaccines that have high effectiveness rates according to clinical trial results. However, various conspiracies have proliferated on various social media platforms from anti-vaxxers across the country. Perhaps a scientific explanation of how the new COVID-19 vaccines function will quell misunderstandings.

Both the Moderna and Pfizer vaccines utilize messenger RNA (mRNA), a single-stranded molecule of RNA that creates proteins. This mRNA contains a specific part of the coronavirus’s genetic code that researchers identified as a vaccine candidate. Researchers wrapped this mRNA in bubbles made out of lipid nanoparticles, a pharmaceutical drug delivery system that protects the mRNA. This combination is then put into a saline solution (a mixture of sodium chloride and water) and then injected into the upper arm, where lymph nodes are.

Once injected into the body, the mRNA enters specialist immune cells in the lymph nodes. The mRNA then travels to the cell’s cytoplasm, where ribosomes are stored. These ribosomes “scan” the mRNA and create a spike protein, similar to one that would be created from a coronavirus infection. The protein spikes then protrude out of the cell, allowing other immune cells to interact with them. These spikes do not cause any actual disease because they are merely synthetic previews of the actual coronavirus that immune cells can learn from.

There are three ways that the coronavirus can be fought with these protein spikes. One way is that immune cells called B-cells can lock onto the protein spikes and, with the aid from helper T-cells, can secrete antibodies. If a coronavirus infection enters the body, these antibodies will latch onto the coronavirus’ spikes, simultaneously preventing further infection and marking it for extermination.

Another way is that if the specialist immune cell dies, its protein spikes can be taken up by an antigen-presenting cell. This cell digests these proteins and presents a protein spike fragment on its surface. Helper T-cells can identify the foreign substance and tell other immune cells to fight the infection.

The antigen-presenting cell can also present its protruding protein spike fragments to killer T-cells. These cells can become activated by the protein spike fragments, learning to identify and kill infected cells.

These vaccines are a significant stepping stone to the fight against COVID-19. However, it is just as important to note that this process is still new and that there are still many unanswered questions from the research. For example, it is unknown if the vaccines will prevent the transmission of COVID-19. That is why it is still urgent for everyone to do their part by wearing masks and social distancing daily. If all of America manages to follow the rules and regulations, then with the addition of a potentially successful vaccine, perhaps 2021 will be a much more promising year.