Effectiveness and side effects of Moderna versus Pfizer COVID-19 vaccines


COVID-19 has claimed many lives since it began to spread in 2020. Thanks to the efforts of science and technology, scientists were able to develop a series of vaccines to reduce its spread and negative effects. The development of these vaccines was done in record time, since a technology was known that could be capable of producing the proteins that had to be activated to fight the virus. Pfizer and Moderna developed two of these vaccines using mRNA technology. In this paper, a comparison and contrast of these vaccines is made in terms of their development, effectiveness, and side effects.

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Scientists have worked unprecedentedly to develop a vaccine to stop the spread of COVID-19, which has claimed many lives worldwide. Prior to these discoveries, prophylactic measures were recommended to control contagion through social distancing, use of masks, and frequent hand washing (Shmerling, 2021). Although these measures have been somewhat effective, it was necessary to have a drug to reduce the number of cases and deaths that were occurring on a daily basis. With the use of new technology and existing scientific knowledge, pharmaceuticals were able to alter the genetics of the virus in such a way that its mutation and resistance became more difficult. The vaccines that we currently use contain a technique known as mRNA, which causes the body to produce proteins to activate the immune system response to fight the virus (CDC, 2021). Other novel developments are currently in the testing stages, which would increase the availability of other medications to counter this virus. In this essay we are going to compare and contrast two of different types of vaccines available in terms of their formula, effectiveness and possible side effects.

Literature review

The Food and Drugs Administration (FDA) has approved the use of at least three vaccines for preventing COVID-19 contagion. Two of these vaccines are distributed by Pfizer-BioNTech and Moderna (CDC, 2021). The Pfizer-BioNTech vaccine has been approved for people over 16 years of age in two vaccines that must be given 3 weeks in between, while the vaccines for children between 5 to 15 years has an emergency use approval. On the other hand, Moderna’s vaccine can be given to people over 18 years of age in two doses 4 weeks between. With all these vaccines, immunity is supposed to be acquired after two weeks after the second dose (CDC, 2021). These means that in terms of the population that can be vaccinated, Pfizer can reach more groups within the population, including children.

In terms of the technology used to developed the vaccines both, Pfizer and Moderna used the mRNA. The mRNA technique will cause the body to produce the proteins necessary to activate the immune system against the virus (CDC, 2021). The mRNA technique, called mRNA-1273 for Moderna and BNT162b2 for Pfizer, contains encapsulated lipid nanoparticles that encode the protein that is activated by COVID-19 (Baden, 2021). These vaccines could be developed quickly by pharmaceutical companies because there was already some knowledge about mRNA for more than a decade. In the case of COVID-19, vaccines´ development only needed the correct information about the genetic sequence of the virus in order for the vaccine to be manufactured using synthetic materials. This same technology had already been proved successful in preventing influenza, Zika virus, Ebola virus, and other bacterial or parasitic infections (Maruggi,, 2019).

The effectiveness of vaccines has been determined through extensive clinical studies in different groups of populations. For example, in a study with 30,420 participants it was found that mRNA technology was effective in preventing COVID-19 contagion with a 94.1% effectiveness, including in patients with severe cases and people older than 65 years old (Baden, 2021; Koff, 2021). On this matter, Nanduri (2021) found that in the nursing home population the effectiveness of Moderna’s vaccine could reach up to 92%, but with the delta variant it fell to 53.1%. In the case of the Pfizer vaccine, the level of effectiveness was estimated at 95% according to the study carried out by Polack (2020). On the other hand, the study by Kaiser (2021) found that dialysis patients who received Moderna’s vaccine had higher anti-S-antibody titers than those vaccinated with Pfizer. It can be concluded that when it comes to the effectiveness of these vaccines, both have a very similar levels, although the Pfizer vaccine the level appears to be around 3% higher.

In the first studies on the vaccines´ side effects, it was suggested that people could develop certain problems such as biodistribution and persistence of the induced immunogen expression, autoreactive antibodies, toxic effects of any non-native nucleotides or delivery system components (Wang, Kream & Stefano, 2020). However, according to the most recent literature, the most common side effects that occur from the application of these vaccines could be: pain at the injection site, pain or swelling in the lymph nodes of the arm where the vaccine was administered, fatigue, headache, muscle or joint pain, nausea and vomiting, or fever and chills, specially after the second dose (Jackson,, 2021). Koff (2021) also found that these sides effects can be experimented in older adults, but in mild to moderate levels. A serious side effect that has been identified in some patients is anaphylaxis or other allergic reactions, which has occurred mainly in people who have had reactions to other vaccines in the past (Kim,, 2021). These reactions occur by residual non-human proteins, preservatives or stabilizers included in the vaccines´ formula (Kim,, 2021). One cannot fail to mention that these vaccines have been associated with thrombosis with thrombocytopenia deaths, but at this time they were associated with the Johnson & Johnson vaccine (See, 2021). However, this study presents the cases reported in the VAERS system and had not been peer-reviewed.



Literature cited

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