COVID-19 is caused by infection with a new coronavirus, called SARS-CoV-2. The first cases of this infection was reported in China at the end of 2019. Many companies and institutions worldwide started working on vaccines to address the spread of the disease. Pfizer and Moderna vaccines were among the first vaccine candidates that finished the necessary sets of trials and were approved for emergency use in many countries, including the United States.
Pfizer
Pfizer is one of the leading pharmaceutical organizations that developed an effective COVID-19 vaccine, which is currently being used in the UK and the USA, and other countries as of December 2020.1 Pfizer’s COVID-19 vaccine has been approved for emergency use authorization (EUA) by the FDA due to the urgency of the public health issue and related negative consequences caused by the pandemic.2 This EUA is for individuals aged 16 or older. In the United States, CDC and FDA continue to monitor vaccine safety using the existing robust system and a new system, called v-safe.3
Pfizer’s mRNA COVID-19 vaccination process consists of two shots administered 21 days apart.4 It has been found that the effectiveness of the vaccine after the first shot is approximately 52%, while its effectiveness after the second shot reaches around 95%.5 One of the peculiarities of the Pfizer vaccine is its storage temperature of -70°C, which can be challenging to distribute this vaccine, especially in certain areas or facilities with no appropriate freezer.6 The vaccine received an EUA in people 16 years of age or older due to the lack of children and adolescents among the participants of trials. Due to the fact that these age-groups are not regarded as the ones at a high risk of developing severe outcomes associated with the infection, this cohort was not included in initial trials.7 However, the trial to test this vaccine in children is on-going. The implemented trials suggest that vaccinated people were considerably less likely to develop serious side effects. These side effects were pain and swelling in the arm, headaches, and chills were documented.4 Such side effects as fever, headaches, and chills were more common after the second shot. Since the effectiveness of Pfizer is over 95%, researchers and practitioners expect that it will contribute significantly to the effort aimed at addressing the COVID-19 pandemic.
Moderna
Moderna introduced its mRNA COVID-19 vaccine that goes under the name mRNA-1273.8 The vaccine was approved for EUA by the FDA in December 2020. The vaccine is provided in two shots in the upper arm muscle 28 days apart and is recommended for individuals older than 18 years old.8 The results of the clinical trials suggest that the effectiveness of the two-dose Moderna vaccine reaches 94.1%. The trial participants included the necessary number of people of different age, race, sex, and ethnicity. One of the benefits of the vaccine is the fact that it can be stored between -20°C and -15°C (-13°F and 5°F). Therefore, Moderna vaccine can be easily distributed in a wider range of countries and communities as compared to Pfizer COVID-19 vaccine. The Phase 3 clinical trial is still ongoing and will continue to follow participants for two years to examine long-term safety, duration of protection and efficacy against SARS-CoV-2 infection. Possible side effects were reported including swelling and pain of the site of the shot, as well as chills and headaches.8
Also, it is reported that the trials of Moderna COVID-19 vaccine now involve younger participants, aged 12-18 to reach the necessary number of participants (3,000 people).7 Notably, these trials face certain challenges as younger participants’ parents are reluctant to provide their permission due to minimal risks related to being infected and still largely unknown outcomes of the vaccine on children’s health.7 As for lactating women or pregnant women, CDC has recommended them to discuss with their healthcare providers to decide whether to get the vaccine.9
Pfizer Vaccine vs Moderna Vaccine
In sum, the effectiveness of both Pfizer and Moderna mRNA vaccines, when 2-dose vaccine is administered, is approximately 95%, which is a high percentage making the vaccines appropriate for the use in people older than 18 years old. Pfizer and Moderna vaccines have been authorized for us under emergency use authorization (EUA) due to the threats associated with the rapid spread of COVID-19. The use of these vaccines in such groups as individuals under 16 years old, pregnant women, and breastfeeding females is still being researched. Both vaccines are not allowed if a person had severe or immediate allergic reactions to any of the components of the vaccines.10 The second shot of both vaccines is not allowed if a person had a severe or immediate allergic reaction during the first shot. Both vaccines may have similar side effects, including swelling and pain in the upper arm, chills, and headaches. The storage temperatures of Pfizer and Moderna vaccines differ considerably, making the Moderna vaccine more easily to be distributed.
Due to the reported effectiveness of Pfizer and Moderna vaccines, everyone should consider getting vaccinated when they are made available to them. The spread of COVID-19 and its detrimental effects on people’s health make vaccine the optimal option for people and countries. At this time, many people are waiting for their turn to get vaccinated. However, once most people who want to be vaccinated get vaccinated, we will soon need to discuss how to address vaccine hesitancy to ensure that we achieve herd immunity. Stay tuned for our quick overview of techniques and tools in the next issue.
References
Hopkins Tanne, J. (2020). Covid-19: FDA panel votes to authorise Pfizer BioNTech vaccine. BMJ, m4799.
U.S. Food and Drug Administration. (2020). Pfizer-BioNTech COVID-19 vaccine. Web.
Centers for Disease Control and Prevention. (2020). Vaccine safety monitoring and reporting in your facility. Web.
Centers for Disease Control and Prevention. (2020). Information about the Pfizer-BioNTech COVID-19 vaccine. Web.
Mahase, E. (2020). Covid-19: UK approves Pfizer and BioNTech vaccine with rollout due to start next week. BMJ, 371.
Mahase, E. (2020). Covid-19: What do we know about the late stage vaccine candidates? BMJ, 371.
Weintraub, K. (2021). Moderna struggles to find 3,000 adolescent volunteers needed for COVID-19 vaccine trial.USA Today. Web.
Centers for Disease Control and Prevention. (2020). Information about the Moderna COVID-19 vaccine. Web.
Centers for Disease Control and Prevention. (2021). Vaccination considerations for people who are pregnant or breastfeeding. Web.
Centers for Disease Control and Prevention. (2020). COVID-19 vaccines and allergic reactions. Web.