COMPARISON OF COVID-19 VACCINES – WHICH ONE IS BETTER?

Being vaccinated does not mean that we can throw caution to the wind and put ourselves and others at risk, particularly because research is still ongoing into how much vaccines protect not only against disease but also against infection and transmission.

Equitable access to safe and effective vaccines is critical to ending the COVID-19 pandemic, so it is hugely encouraging to see so many vaccines proving and going into development. WHO is working tirelessly with partners to develop, manufacture and deploy safe and effective vaccines? 

But it’s not vaccines that will stop the pandemic, it’s vaccination. We must ensure fair and equitable access to vaccines, and ensure every country receives them and can roll them out to protect their people, starting with the most vulnerable.

At present 287 vaccine candidates are under development, out of which 102 are in clinical phase and 185 are in preclinical phase. Several different types of potential vaccines for COVID-19 are in development, including:

• Inactivated or weakened virus vaccines, which use a form of the virus that has been inactivated or weakened so it doesn’t cause disease, but still generates an immune response.
• Protein-based vaccines, which use harmless fragments of proteins or protein shells that mimic the COVID-19 virus to safely generate an immune response.
• Viral vector vaccines, which use a safe virus that cannot cause disease but serves as a platform to produce coronavirus proteins to generate an immune response.
• RNA and DNA vaccines, a cutting-edge approach that uses genetically engineered RNA or DNA to generate a protein that itself safely prompts an immune response.

Because COVID vaccines have only been developed in the past months, it’s too early to know the duration of protection of COVID-19 vaccines. Research is ongoing to answer this question. However, it’s encouraging that available data suggest that most people who recover from COVID-19 develop an immune response that provides at least some period of protection against reinfection – although we’re still learning how strong this protection is, and how long it lasts.

While we are learning more, we need to do everything possible to stop the spread of the virus in order to prevent mutations that may reduce the efficacy of existing vaccines. This means staying at least one meter away from others, covering a cough or sneeze in your elbow, frequently cleaning your hands, wearing a mask and avoiding poorly ventilated rooms or opening a window. 

LET’S COMPARE THE VACCINES TO UNDERSTAND WHICH ONE IS BETTER?

So, how do they differ? Here’s what we know so far.

Vaccines from Pfizer-BioNTech, Moderna, and Johnson & Johnson are being administered in the U.S. right now, and others are on track to do the same. Even though you will likely not be able to choose which vaccine you will get, it’s still helpful to know how each one is different.

With that in mind, we mapped out a comparison of the most prominent vaccines so far.

COMPARATIVE ANALYSIS OF DIFFERENT VACCINES

1. PFIZER & BIONTECH (First COVID-19 vaccine to receive an FDA EUA)

• Type: It is mRNA-based vaccine
• Status: Emergency use in the U.S.; authorized for use in the European Union (under the name Comirnaty). Approved by majority of countries but not approved in India as of now.
• Efficacy: 95% effective at preventing symptomatic disease.
• Efficacy against virus mutation: vaccine was found to be more than 95% effective against severe disease or death from the variants first detected in the United Kingdom (B.1.1.7) and South Africa (B.1.351) in two studies based on real-world use of the vaccine.
• Recommended for Age group: Anyone 12 or older.
• Dosage: Two shots, 21 days apart
• Common side effects: Chills, headache, pain, tiredness, and/or redness and swelling at the injection site, all of which generally resolve within a day or two of rest, hydration, and medications like acetaminophen. (If symptoms don’t resolve within 72 hours or if you have respiratory symptoms, such as cough or shortness of breath, call your doctor.) On rare occasions, mRNA vaccines have appeared to trigger anaphylaxis, a severe reaction that is treatable with epinephrine (the drug in Epipens®). For that reason, the Centers for Disease Control and Prevention (CDC) requires vaccination sites to monitor everyone for 15 minutes after their COVID-19 shot, and for 30 minutes if they have a history of severe allergies or are taking a blood thinner.
• Storage: It has required shipping in ultra-cold temperature-controlled units (-94 degrees Fahrenheit). In mid-February, the company submitted new data to the FDA demonstrating the stability of the vaccine at temperatures more commonly found in pharmaceutical refrigerators and freezers. Approval would make the vaccine easier to distribute.

2. MODERNA (Second COVID-19 vaccine to receive an FDA EUA)

• Type: It is also mRNA-based vaccine.
• Status: Emergency use in the U.S.; authorized for use in the European Union. Approved by majority of contries but not approved in India as of now.
• Efficacy:1% effective at preventing symptomatic infection in people with no evidence of previous COVID-19 infection.
• Efficacy against virus mutation: No evidence available. Research is going on.
• Recommended for Age Group: Adults 18 and older.
• Dosage: Two shots, 28 days apart
• Common Side Effects: side effects can include chills, headache, pain, tiredness, and/or redness and swelling at the injection site, all of which generally resolve within a day or two. On rare occasions, mRNA vaccines have appeared to trigger anaphylaxis, a severe reaction that is treatable with epinephrine (the drug in Epipens®). For that reason, the CDC requires vaccination sites to monitor everyone for 15 minutes after their COVID-19 shot, and for 30 minutes if they have a history of severe allergies.
• Storage: The Moderna vaccine can be shipped and kept in long-term storage in standard freezer temperatures, and stored for up to 30 days using normal refrigeration, making it easier to distribute and store.

3. JOHNSON & JOHNSON (Third COVID-19 vaccine to receive an FDA EUA)

• Type: It is a carrier, or virus vector-based vaccine.
• Status: Emergency use in the U.S.; authorized for use in the European Union (under the name Janssen). Continues to be recommended by the FDA and CDC after a pause because the benefits outweigh the risks. Not available in India as of now.
• Efficacy: 72% overall efficacy and 86% efficacy against severe disease in the U.S.
• Efficacy against virus mutation: There was 64% overall efficacy and 82% efficacy against severe disease in South Africa, where the B.1.351 variant was first detected.  
• Recommended for Age Group: Adults 18 and older.
• Dosage: Single shot.
• Common Side effects: Fatigue, fever headache, injection site pain, or myalgia (pain in a muscle or group of muscles), all of which generally resolve within a day or two. It has had noticeably milder side effects than the Pfizer and Moderna vaccines, according to the FDA report released in late February. No one suffered an allergic reaction in clinical trials for the vaccine, according to the company.
• Storage: In comparison to the Pfizer and Moderna vaccines, this one is easier to store (in refrigerator temperature).

4. OXFORD-ASTRAZENECA (Sold under the brand names Covishield and Vaxzevria)

• Type: Viral vector-based vaccine.
• Status: Not available in the U.S., authorized for use in the European Union (under the name Vaxzevria) and in India (Covishield).
• Efficacy: AstraZeneca updated its data analysis of its phase 3 trials in March, showing its vaccine to be 76% effective at reducing the risk of symptomatic disease 15 days or more after receiving the two doses, and 100% against severe disease. The company also said the vaccine was 85% effective in preventing COVID-19 in people over 65.
• Efficacy against virus mutation: A paper in early February (not yet peer-reviewed) cited 74.6% efficacy against the B.1.1.7 variant. However, the vaccine did not protect as well against mild and moderate cases in people infected with the B.1.351 variant. On 22 May 2021, Public Health England published an analysis showing that, for symptomatic COVID-19 infection after the second dose, the vaccine is 66% effective against B.1.1.7 (alpha) variant, and 60% against B.1.617.2 (delta) variant.
• Recommended for Age Group: Adults 18 and older
• Dosage: Two doses, four to 12 weeks apart
• Common Side effects: Tenderness, pain, warmth, redness, itching, swelling or bruising at the injection site, all of which generally resolve within a day or two.
• Storage: It can be stored, transported, and handled in normal refrigeration for at least six months.

5. NOVAVAX

• Type: Protein adjuvant.
• Status: Still completing clinical trials.
• Efficacy:4% efficacy in reducing mild and moderate disease, 100% against severe disease from the original strain of COVID-19.
• Efficacy against virus mutation:3% efficacy in the United Kingdom, where the B.1.1.7 variant is circulating.
• Recommended for Age Group: The vaccine is being studied in adults ages 18-84.
• Dosage: 2 doses, three weeks apart.
• Common Side effects: While the Novavax vaccine is still being studied, early trials have shown no adverse events.
• Storage: It is also simpler to make and can be stored in a refrigerator.

6. SPUTNIK-V

• Type: Non-replicating Viral vector (Modified Adeno).
• Status: It was initially approved for distribution in Russia and then in 59 other countries (as of April 2021) on the preliminary results of Phase I–II studies eventually published on 4 September 2020. On 12 April 2021, India approved the use of Sputnik V vaccine for emergency use against COVID-19 based on strong immunogenicity data.
• Efficacy: On 2 February 2021, an interim analysis from the trial was published in The Lancet, indicating 91.6% efficacy without unusual side effects.
• Efficacy against virus mutation: No data available.
• Recommended for Age Group: Adults 18 and older.
• Dosage: Two shots, second dose after 28 days.
• Common Side effects: No serious side effects have been recorded after taking the Sputnik V shot. There have been instances of hypertension, hemorrhagic stroke, and thrombosis, but there’s no confirmation of the vaccine shot being the reason behind it.
• Storage: The vaccine can be formulated in two ways: as a ready-to-use solution in water that is frozen at the common home-freezer storage temperature of −18 °C or 0 °F or lower; and as a freeze-dried powder, “Gam-COVID-Vac-Lyo”, whose storage temperature is above freezing, 2–8 °C or 36–46 °F, at the common home-refrigerator temperature. The freeze-dried powder must be reconstituted with water before use.

# Sputnik-Light, a single-dose version, is also being developed to speed up vaccination outside Russia. It will offer less protection than the two-dose versions, but it is still expected to reach an efficacy of 85%.

In India, Dr Reddys Laboratories Limited and Sputnik LLC are jointly conducting multi-centre, phase II/III adaptive clinical trial to assess safety and immunogenicity of Gam-COVID-Vac combined vector vaccine.

COVAXIN

• Type: Inactivated virus-based COVID-19 vaccine
• Status: On 2 January 2021, BBV152 (marketed as Covaxin), became the first domestically-produced vaccine to receive approval from the Drug Controller General of India for its emergency or conditional usage.
• Efficacy: On 3 March 2021, Bharat Biotech reported that Covaxin showed 81% efficacy in a phase 3 trial with 25,800 participants.
• Efficacy against virus mutation:

B.1.1.7 variant: In December 2020, a new SARS‑CoV‑2 variant, B.1.1.7, was identified in the UK. An in vitro study on this variant was carried out and preliminary results show Covaxin to be effective in neutralizing this strain.

B.1.617 variant: In April 2021, the Indian Council of Medical Research reported that the vaccine has shown promising results in neutralizing the strain B.1.617.

P.2 variant: In May 2021, a joint investigation by the scientists of National Institute of Virology (NIV) India, found the vaccine effective in neutralizing the P.2 (previously known B.1.1.28) strain.

• Recommended for Age Group: COVAXIN has been approved for restricted use in emergency situation in individuals 18 years of age and older. In May 2021, Drugs Controller General of India (DCGI) approved clinical trials in the age group of 2 to 18 years. The trails are conducted at AIIMS Delhi and Patna. As many as 54 children had registered at the AIIMS Patna.
• Dosage: Two shots, 28 days apart.
• Common Side effects: Side effects that have been reported in the fact sheet of Bharat Biotech COVID-19 vaccine (COVAXIN) include Injection site pain, swelling, redness, itching, headache, fever, malaise/body ache, nausea, vomiting, and Rashes. A severe allergic reaction may very rarely occur after getting a dose of COVAXIN. These may not be all the possible side effects of COVAXIN. Serious and unexpected side effects may occur. COVAXIN is still being studied in clinical trials.
• Storage: Covaxin can be easily and conveniently stored at 2–8 degrees celsius, which is a regular refrigerator temperature.

CONCLUSION

Because COVID vaccines have only been developed in the past months, it’s too early to know the duration of protection of COVID-19 vaccines. Research is ongoing to investigate the vaccines for their therapeutic efficacy and toxicities. However, it’s encouraging that available data suggest that most people who recover from COVID-19 develop an immune response that provides at least some period of protection against reinfection – although we’re still learning how strong this protection is, and how long it lasts.

The COVID-19 vaccines produce protection against the disease, as a result of developing an immune response to the SARS-Cov-2 virus. Developing immunity through vaccination means there is a reduced risk of developing the illness and its consequences. This immunity helps you fight the virus if exposed. Getting vaccinated may also protect people around you, because if you are protected from getting infected and from disease, you are less likely to infect someone else. This is particularly important to protect people at increased risk for severe illness from COVID-19, such as healthcare providers, older or elderly adults, and people with other medical conditions.

REFERENCES

1. Vaccines and related biological products advisory committee meeting. U.S. Food and Drug Administration. https://www.fda.gov/media/144245/download.
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