The COVID-19 Vaccine: How Does It Work?

Here are the facts on the amazing science behind the quickest vaccine ever produced
By Andrea Arias

In April 2020, amidst the start of the COVID-19 pandemic, when the question “When will the vaccine be ready?” first arose, the New York Times released an article where they projected that the vaccine could take until 2033, even though health professionals were aiming to get it done by August 2021. Little did they know that in a little over eight months, the first vaccine for COVID-19 would be approved. Remarkable.

Before the COVID-19 vaccine was created, the quickest vaccine was for the mumps in the 1960s, and that vaccine took 4 years. So, why was the COVID vaccine projected to take so long, and how were we able to get it done so quickly?

–Vaccine Development Process–

Vaccines have always been projected to take years, this is due to the process that takes place to create a vaccine. The process of creating a vaccine is done by using a deactivated version of the virus or a “live but mild version” of the virus that has grown to be less severe. This is then injected into someone, which allows our B cells to create and synthesize antibodies to fight the virus if we are ever to come in contact with a live version.

While this is the traditional and most common vaccine (flu vaccines were created using this method), due to the severity and need for a Covid vaccine as quickly as possible, some companies decided to use a new method this time. Since SARS-CoV-2 was a new virus (SARS-CoV-2 is the name of the virus and COVID-19 stands for the disease, Coronavirus Disease 2019), with no previous research or understanding of the virus it would be difficult for a vaccine to be created.

–mRNA Vaccines–

The new method used to create the COVID-19 vaccine is called an mRNA vaccine. mRNA is messenger RNA, and its job is to produce proteins. So, how does an mRNA vaccine work? Well, by encoding mRNA with the information needed to produce the SARS-CoV-2 spike protein, this allows the body to then realize that this protein is an invader and produces antibodies to fight it. Essentially, it is the same process as a traditional vaccine, but instead of using a version of the virus, a synthetic mRNA is injected and binds to human cells and then creates a “spike” protein (which is what allows coronavirus to infect other cells).

Only two companies decided to take the approach of using an mRNA vaccine, these two were Moderna and Pfizer. The latter is a company under a German government program that is pushing for a vaccine, and the former is a company under the Operation Warp Speed started by the U.S. Department of Health & Human Services. With the press release from Moderna and Pfizer, we are able to learn how Phase 1/3 went, and how quickly these two companies were able to come up with a solution and vaccine in just 8 short months. According to BioSpace, by Phase I both Moderna and Pfizer achieved outstanding results in non-human models that produced sufficient CD4+ T cells against the virus (see graphic, below). CD4+ cells are “helper” cells that trigger the body’s response to infections.

This is being attached to T cells which are the key white blood cells for the immune system. Along with this, within the first phase both Moderna and Pfizer realized the importance and essential need for a two-dose vaccine. This was discovered because it was found that 43 days or two weeks after the second dose participants had the same level of antibodies as people who had recovered from the virus. While during Phase I Moderna only managed to create a protein, mRNA-1273, that could protect against replication in the lungs of SARS-CoV-2, in a later phase they found how to also prevent infection from the virus. 

–Other Promising Vaccines–

While the mRNA vaccines by Moderna and Pfizer have been the quickest to be created and released, they are not the only vaccines being created. There are three other types of vaccines being used by other companies to help put a stop to this pandemic. Novaxax is creating a protein-based vaccine, which uses related versions of the spike protein and injects this into a person. By doing this, the protein tutors the immune system in how to fight the virus. This, in turn, allows cells to be pushed into the frontlines, dedicated to fighting the virus. Protein vaccines have been around much longer and have been proven to be highly effective, but they are slower to produce than mRNA vaccines.

Research on the Novavax vaccine has found that it has the highest neutralizing antibodies reported yet. Another type of vaccine is the adenovirus-based vaccine; Johnson & Johnson as well as AstraZeneca have been trying to create this type of vaccine, and it appears that Johnson & Johnson has succeeded. Adenovirus-based vaccines are prepared by inserting a transgene cassette into the adenoviral backbone by homologous recombination, which is an exchange of genetic information from similar or identical molecules or DNA or RNA. According to the CDC, this is a vaccine that is taken orally and is only used in the military, and none exist for public or general use in the U.S. Similarly to the protein vaccine, adenovirus vaccine technology has existed for several years but has not been used to create a general vaccine for public use.

–Timeline of Historic Vaccines–

  • •December 31, 2020 The first case of Coronavirus Disease 2019 was reported in Wuhan, China.

    •January 29, 2020 The first lab-grown 2019-nCov was created. This at the time was the first step for a traditional version of a vaccine for COVID-19 to be created. 

    •February 13, 2020 A radiologist from Wuhan published findings of a chest CT scan which suggested four evolutionary stages of COVID-19, these four stages being the early stage (0–4 days), progressive stage (5–8 days), peak stage (9–13 days), and absorption stage (≥14 days). Within this time, researchers found that there was an abnormality within the patient’s lungs. 

    •February 17, 2020 Just a few days later, it was revealed that warmer weather and humidity might not affect the spread of COVID-19 like many had suggested. This posed a problem as, unlike the flu, a person is likely to contract the disease at any point and time of the year. 

    •February 24, 2020 With shocking speed, Moderna, one of the companies to later release a well-developed vaccine, sent a vaccine to phase 1 testing in the U.S.

    •February 26, 2020 Novaxax announces possible candidate against the Coronavirus.

    •March 16, 2020 Moderna vaccine testing begins.

    •March 30, 2020 Johnson & Johnson announced a lead candidate for their version of the COVID-19 virus. The Janssen vaccine is not a mRNA vaccine but an adenovirus based vaccine.

    •April 29, 2020 The first group for Phase I testing is injected with the Pfizer vaccine.

    •May 15, 2020 The Trump administration announces ‘Operation Warp Speed.’ This is done to speed up the process of the vaccines currently being tested, which at the time were Moderna, Pfizer, and Johnson & Johnson.

    •May 25, 2020 Novavax initiates the start of Phase 1/2 testing in Australia, for their NVX-CoV2373, protein-based vaccine.

    •May 29, 2020 Moderna starts their evaluation of the vaccine in Phase II. They ran a placebo-controlled experiment to confirm the dose and evaluate the safety of the vaccine.

  • •May – July 2020 Seven pharmaceutical companies were approved into ‘Operation Warp Speed.’ These were: Johnson & Johnson, Merck & Co., Moderna Inc., University of Oxford in collaboration with AstraZeneca Plc, and Novavax, Pfizer Inc. *Note: Pfizer was not initially involved but a deal was made for 100 million doses of their vaccine in mid-July*

    •June 5, 2020 The BBC announced for AstraZeneca that they will begin producing potential Covid vaccines. Around this time, AstraZeneca’s vaccine also passed to Phase I. AstraZeneca’s vaccine is not an mRNA vaccine but instead a double-stranded DNA vaccination rather than a single-stranded mRNA. The vaccine is called ChAdOx1 nCoV-19 or AZD1222.

    •July 27, 2020 Moderna begins Phase III testing of their mRNA-1273 vaccine. On this day, Pfizer also chose their lead mRNA vaccine to advance into Phase II.

    •August 24, 2020 Novavax advances to Phase II of Phase 1/2 clinical trial of their NVX-CoV2373 vaccine.

    •August 31, 2020 AstraZeneca’s advances to Phase III clinical trials in the U.S. for all adult groups. 

    •September 2, 2020 AstraZeneca temporarily pauses clinical trials of their Covid-19 vaccine, AZD1222, due to an unexplained illness that occured in the UK during their Phase III testing there. The clinical trials have to be stopped to ensure the safety of all participants. 

    •November 8, 2020 Pfizer conducted their Phase III trail revealing an efficiency rate above 90%

    •December 8, 2020 The first person to receive the Pfizer vaccine is a 90-year-old woman in the United Kingdom.

    Photograph: Jonny Weeks/NHS England/Getty Images

    •December 10, 2020 Pfizer publicized the results of the Phase III clinical trial. There were 43,448 participants, 21,720 of which received BNT162b2, the vaccine, and 21,728 received a placebo, using the two-dose regimen of BNT162b2, which was given 21 days apart. This demonstrated the vaccine to be 95% effective against COVID-19.

  • •December 11, 2020 The U.S. FDA approved the first Covid vaccine for emergency use in the U.S., the Pfizer vaccine.

    •December 18, 2020 The FDA approved the Moderna vaccine to be the second vaccine approved for emergency use in the U.S.

    •December 20, 2020 The U.K. authorized the use of the AstraZeneca covid-19 vaccine.

    •December 28, 2020 Novavax announces the start of their PREVENT-19 Phase III trial in the U.S. and Mexico.

    •January 8, 2021 A Pfizer press release announced that their Covid-19 vaccine is effective against the multiple mutations recently discovered.

    •January 28, 2021 In a press release by Novavax, they stated that in their Phase III trials in the UK proved their vaccine is 89.3% effective against Covid-19. (This test was conducted against the new variant in the UK as well as during a time of high infectious rate, meaning they are looking to create a strong vaccine to stop the multiple mutations of Covid-19, including the one in South Africa.)

    •February 3, 2021 AstraZeneca announces that their vaccine is 100% effective against severe cases of Covid-19, making it likely the most effective vaccine to be released.*

    *Note: this is only against severe cases, hospitalizations, and death; it is still likely to get coronavirus but the likelihood of being hospitalized is very slim from these results.

    •February 4, 2021 Johnson & Johnson requested emergency authorization from the FDA for their COVID-19, vaccine which has been found to be 72% effective, less than both Moderna and Pfizer but large nonetheless for such a short period of time. The J&J vaccine was also able to test against the new variant of the virus present in the U.S., South Africa and Latin America at this time.

    Photo Illustration by Pavlo Gonchar/SOPA Images/LightRocket via Getty Images)

    •February 7, 2021 Africa suspends the rollout of the AstraZeneca vaccine due to minimal protection it provided for the variant identified there.

For more constant updates on new vaccines and other vaccines not listed above check out the New York Times Covid-19 Vaccine Tracker which is updated constantly. They also do a great job in breaking down all the vaccines and their purposes.

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