The landscape of COVID-19 vaccines has evolved rapidly since the initial rollout in late 2020. Websites like compare.edu.vn aim to provide clear and comparative information to help individuals understand these changes. Initially, the focus was on preventing symptomatic disease from the original SARS-CoV-2 virus. However, as the virus mutated and new variants emerged, vaccines have been updated to maintain their effectiveness. This article delves into a comparison of the currently available COVID-19 vaccines in the U.S. – Pfizer-BioNTech, Moderna, and Novavax – to help you understand their similarities, differences, and how they address the evolving strains of the virus.
Pfizer-BioNTech (Comirnaty) Vaccine: An mRNA Pioneer
The Pfizer-BioNTech vaccine, marketed as Comirnaty, holds the distinction of being the first COVID-19 vaccine to receive full FDA approval for individuals aged 16 and older in August 2021. Prior to this, it was granted Emergency Use Authorization (EUA) in December 2020, marking a significant milestone in the fight against the pandemic. This vaccine utilizes messenger RNA (mRNA) technology, a groundbreaking approach to vaccine development.
Status: Continuously Updated for Emerging Strains
Since its initial release in December 2020, the Pfizer-BioNTech vaccine has undergone several updates to target newly emerging virus variants. The original formula was designed to combat the initial SARS-CoV-2 virus. However, recognizing the virus’s ability to mutate, subsequent versions have been developed to address different iterations of the Omicron strain.
Comparison of Pfizer-BioNTech COVID-19 vaccine, highlighting its updated formulations targeting new virus strains.
In 2022, “bivalent” vaccines were introduced, offering protection against both the original virus and the Omicron variants BA.4 and BA.5. The year 2023 saw the deployment of a monovalent shot specifically targeting the XBB lineage of Omicron. Most recently, in 2024, a new updated vaccine has been formulated to combat KP.2, a variant that circulated earlier in the year. It’s crucial to note that previous vaccine versions are no longer in use, emphasizing the importance of staying updated with the latest recommendations.
Who Can Get It: Broad Eligibility with Specific Guidelines
The Pfizer-BioNTech vaccine is authorized for individuals aged 6 months and older. The Centers for Disease Control and Prevention (CDC) provides specific recommendations for different age groups, advising that individuals who have recently had COVID-19 may consider delaying vaccination for 3 months.
- Children ages 5 to 11 years: Recommended to receive one dose of the 2024-2025 updated vaccine.
- People ages 12 and older: Recommended to receive one dose of the 2024-2025 updated vaccine.
- Individuals 65 years and older and those who are moderately or severely immunocompromised: May receive a second dose six months after their initial dose. Immunocompromised individuals should consult with their healthcare providers regarding additional doses.
Possible Side Effects: Mostly Mild and Transient
The most commonly reported side effects of the Pfizer-BioNTech vaccine are generally mild and localized. These include pain, redness, or swelling at the injection site. Systemic side effects, affecting the rest of the body, may include tiredness, headache, muscle pain, chills, fever, or nausea. These side effects typically resolve within a few days.
While serious side effects are rare, they can occur. Anaphylaxis, a severe allergic reaction, is a possibility but is treatable with epinephrine.
FDA Warnings: Addressing Rare Heart Inflammation Risks
The FDA has issued a warning regarding a rare but serious side effect associated with mRNA vaccines, including Pfizer-BioNTech’s: myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the outer lining of the heart). These conditions have been observed in adolescents and young adults, more frequently after the second dose. In the majority of cases, the inflammation resolves on its own without requiring treatment.
How It Works: Harnessing mRNA Technology
The Pfizer-BioNTech vaccine leverages mRNA technology. It delivers genetic instructions, in the form of mRNA, to the body’s cells. These instructions direct the cells to produce copies of the SARS-CoV-2 spike protein – the characteristic spikes on the virus’s surface. The body recognizes this spike protein as foreign, triggering an immune response. This response involves the activation of immune cells and the production of antibodies. As a result, the body becomes primed to recognize and combat the actual SARS-CoV-2 virus upon future exposure.
How Well It Works: Efficacy Against Current Strains
The 2024-2025 updated Pfizer-BioNTech vaccines were approved based on preclinical studies demonstrating their effectiveness against currently circulating strains. While vaccination may not entirely prevent infection, the primary goal has shifted to preventing severe illness, hospitalization, and death.
Visual representation of the COVID-19 virus, against which vaccines like Pfizer-BioNTech are designed to protect.
Assessing the real-world effectiveness of updated vaccines beyond clinical trials can be complex. Manufacturers develop these vaccines based on preclinical data and predictions about prevalent variants. This process mirrors the approach used for annual flu vaccines. However, according to a CDC summary from November, the 2024-2025 vaccines are anticipated to be effective against dominant strains like KP.3.1.1, as well as emerging variants such as XEC and MC.1. Research also suggests that vaccinated individuals who experience breakthrough infections are less likely to develop Long COVID compared to unvaccinated individuals.
Initial clinical trial data for Pfizer-BioNTech’s original vaccine showed a 95% efficacy in preventing symptomatic COVID-19. Real-world data later indicated that protection from the initial two-dose series waned over time, underscoring the need for updated vaccines and booster doses to maintain robust immunity.
For more detailed information, refer to the FDA’s Pfizer-BioNTech 2024-2025 vaccine fact sheet.
Moderna (Spikevax) Vaccine: Another mRNA Powerhouse
The Moderna vaccine, branded as Spikevax, received full FDA approval for individuals 18 and older in January 2022, building upon its initial EUA granted in December 2020, shortly after Pfizer-BioNTech. Moderna employs the same mRNA technology as Pfizer-BioNTech and demonstrated similarly high efficacy in preventing symptomatic COVID-19 in its initial authorization applications.
Status: Aligned Updates to Combat Variant Evolution
Mirroring Pfizer-BioNTech’s approach, Moderna’s vaccine has been consistently updated to target new virus variants. The original Moderna mRNA vaccine, introduced in December 2020, targeted the original SARS-CoV-2 virus. Since then, it has been updated multiple times to address evolving Omicron strains.
In 2022, Moderna also released “bivalent” vaccines targeting both the original virus and Omicron variants BA.4 and BA.5. A monovalent shot targeting the Omicron XBB lineage followed in 2023, and in 2024, a new updated vaccine was developed to address the KP.2 variant. As with Pfizer-BioNTech, previous versions of the Moderna vaccine are no longer in use.
Who Can Get It: Expanded Age Range and Dosage Recommendations
The Moderna vaccine is authorized for a broad age range, starting from 6 months and older. Similar to Pfizer-BioNTech, the CDC provides specific guidelines, suggesting a 3-month delay in vaccination for those recently infected with COVID-19.
- Children ages 6 months to 4 years: Require multiple doses (refer to the CDC website for specific recommendations), including at least one dose of the 2024-2025 updated vaccine.
- Children ages 5 to 11 years: May receive one dose of the 2024-2025 updated vaccine.
- People ages 12 and older: May receive one dose of the 2024-2025 updated vaccine.
- Individuals 65 years and older and those who are moderately or severely immunocompromised: May receive a second dose six months after the first. Immunocompromised individuals should consult their healthcare provider about additional doses.
Possible Side Effects: Comparable to Pfizer-BioNTech
The side effect profile of the Moderna vaccine is very similar to that of the Pfizer-BioNTech vaccine. Common side effects include pain, redness, or swelling at the injection site, as well as systemic effects such as tiredness, headache, muscle pain, chills, fever, or nausea. These are typically mild and short-lived, resolving within a few days. Rare but serious side effects, including anaphylaxis, are also possible.
FDA Warnings: Similar Heart Inflammation Considerations
The FDA has also issued a warning label for the Moderna vaccine, noting a “likely association” with reported cases of heart inflammation in young adults. This includes both myocarditis and pericarditis, with a higher occurrence after the second dose of the mRNA vaccine. As with the Pfizer-BioNTech vaccine, most cases of inflammation are mild and resolve without treatment.
How It Works: mRNA Mechanism Parallels Pfizer
The Moderna vaccine’s mechanism of action mirrors that of the Pfizer-BioNTech vaccine. It is an mRNA vaccine that instructs host cells to produce the SARS-CoV-2 spike protein. This spike protein then trains the immune system to recognize and mount a defense against it. Subsequently, the immune system is prepared to attack the spike protein if it encounters it again in the context of a real SARS-CoV-2 infection.
How Well It Works: Effective Against Current Variants
The 2024-2025 updated Moderna vaccines, like their Pfizer-BioNTech counterparts, were approved based on preclinical studies demonstrating efficacy against the latest circulating strains. While breakthrough infections can still occur, the vaccines are primarily aimed at preventing severe disease, hospitalization, and death. Real-world effectiveness data collection faces similar challenges as with Pfizer-BioNTech, due to the predictive nature of variant selection for vaccine updates. However, the CDC anticipates that the 2024-2025 Moderna vaccines will be effective against dominant strains like KP.3.1.1 and emerging variants like XEC and MC.1. Studies also indicate a reduced risk of Long COVID in vaccinated individuals who experience breakthrough infections.
Initial Phase 3 clinical trial data for the Moderna vaccine in December 2020 showed approximately 95% efficacy in preventing COVID-19, comparable to Pfizer-BioNTech. Real-world data later confirmed waning protection over time from the initial two-dose series, but booster doses have been shown to restore robust immune protection.
Additional information is available on the FDA’s Moderna 2024-2025 vaccine fact sheet.
Novavax (Nuvaxovid and Covovax) Vaccine: A Protein-Based Alternative
The Novavax vaccine, marketed under the brand names Nuvaxovid and Covovax, represents a different vaccine technology compared to the mRNA vaccines. It was the fourth COVID-19 vaccine to be administered in the U.S. and is currently the only non-mRNA updated COVID-19 vaccine available in the country. This protein adjuvant vaccine demonstrated a 90% efficacy in its clinical trial, performing comparably to the mRNA vaccines in their early trials. A key advantage of the Novavax vaccine is its simpler manufacturing process and refrigerator storage requirements, facilitating easier distribution.
Status: Updated Formula Targeting JN.1 Variant
The FDA authorized an updated COVID-19 vaccine from Novavax in late August 2024 for individuals aged 12 and older. Novavax designed its updated shot to target the JN.1 variant, a predecessor to KP.2. The Novavax 2023-2024 vaccine is no longer available in the U.S. due to expiration of all doses.
Representation of Novavax COVID-19 vaccine, a protein-based option offering an alternative to mRNA vaccines.
Who Can Get It: Approved for Ages 12 and Up
The Novavax vaccine is currently authorized for individuals 12 years and older. Similar to the mRNA vaccines, individuals 65 and older and those who are moderately or severely immunocompromised may receive a second dose six months after their first. Consultation with healthcare providers is recommended for immunocompromised individuals regarding additional doses.
Possible Side Effects: Generally Mild, Rare Heart Inflammation
Common side effects of the Novavax vaccine include injection site tenderness, fatigue, headache, and muscle pain. Clinical trials reported rare cases of myocarditis and pericarditis (six cases in 40,000 participants) and rare severe allergic reactions.
How It Works: Protein Adjuvant Technology
Unlike the mRNA vaccines and viral vector vaccines, Novavax utilizes a protein adjuvant approach. Instead of instructing the body’s cells to produce viral components, the Novavax vaccine directly delivers the coronavirus spike protein itself. This spike protein is formulated as a nanoparticle and cannot cause disease. The adjuvant component enhances the immune response to this protein. Upon injection, the vaccine stimulates the immune system to produce antibodies and T-cell immune responses, providing protection against future infection.
How Well It Works: Broad Protection Against Variants
While the 2024-2025 updated Novavax vaccine targets the JN.1 variant, unlike the Pfizer and Moderna vaccines which target KP.2, Novavax has reported non-clinical data indicating broad cross-neutralizing antibodies against multiple variant strains, including JN.1, KP.2, and KP.3. Similar to mRNA vaccines, assessing real-world effectiveness is challenging due to the predictive nature of vaccine development against evolving variants. However, the CDC anticipates that the 2024-2025 Novavax vaccines will also be effective against dominant strains like KP.3.1.1 and potential future variants like XEC and MC.1.
Earlier studies of the original Novavax vaccine demonstrated 90% overall efficacy against symptomatic infection and 100% efficacy against moderate and severe disease in Phase 3 trials published in The New England Journal of Medicine in December 2021.
Additional information is available on the FDA’s Novavax 2024-2025 vaccine fact sheet.
Conclusion: Choosing the Right Vaccine in a Dynamic Landscape
Comparing the available COVID-19 vaccines reveals both commonalities and key differences. Pfizer-BioNTech and Moderna, both mRNA vaccines, have been at the forefront of the vaccination effort, consistently updated to address new variants. Novavax offers a protein-based alternative, utilizing a different technology but still providing strong protection. All three vaccines have demonstrated effectiveness in preventing severe illness, hospitalization, and death from COVID-19 and are expected to work well against current and emerging strains. The “Strain Compare” aspect highlights the continuous adaptation of these vaccines to the evolving virus. Ultimately, the best COVID-19 vaccine is the one that is available to you and recommended by health authorities. Staying up-to-date with vaccinations remains a crucial tool in protecting yourself and your community against COVID-19.
