Comparing COVID-19 Vaccines: Timelines, Types

The spread of the coronavirus has killed many people around the world, so many countries, in addition to imposing severe coronation restrictions, have pursued to develop an effective vaccine against SARS-CoV-2 viruses. COVID-19 vaccines are simultaneously and more important to humanity than ever before.

In all vaccines, the immune system is stimulated by triggering the immune response to a specific antigen in the virus. In the case of COVID-19, this antigen is typically a specific Spike (S) protein on the surface of the virus, which it typically uses to help attack human cells.

In clinical trials, there are four categories of vaccines: whole virus, protein fragments, viral vector, and nucleic acid structure (RNA and DNA). Some of them try to carry the relevant antigen to the body, while others use the body’s own cells to make viral antigens. In the following, we will introduce and review a number of vaccines produced in this field:

Pfizer-BioNTech

The Pfizer-BioNTech COVID-19 vaccine was sent to the FDA for possible Emergency Use Authorization (EUA) on Friday, November 20, and authorized on December 11. It is an mRNA vaccine that codes for the virus’s spike protein and is encapsulated in a lipid nanoparticle. Once injected, the cells churn out the spike protein, triggering the body’s immune system to recognize the virus. In Phase III trials, it demonstrated 95% efficacy. The Pfizer-BioNTech vaccine requires storage at about -94 degrees F, which requires specialized freezers.

• Type: mRNA
• Doses: 2, 21 Days Apart
• EUA Date: December 11, 2020
• Efficacy: About 95%. Apparently 100% at preventing hospitalization and death.
• Variants: Lab data suggest “quite effective” against the UK variant as well as the South African and Latin American variants.

Moderna

On November 16, Moderna issued a preliminary data readout out of its COVID-19 vaccine, suggesting an efficacy rate of 94.5%. It was authorized by the FDA on December 19. Like the Pfizer-BioNTech vaccine, it is an mRNA vaccine. Unlike that vaccine, however, the Moderna vaccine is stable at 36 to 46 degrees F, about the temperature of a standard home or medical refrigerator, for up to 30 days and can be stored for up to six months at -4 degrees F. It is expected to go to the FDA for consideration for an EUA within days.

• Type: mRNA
• Doses: 2, 28 Days Apart
• EUA Date: December 18, 2020
• Efficacy: About 95%. Apparently 100% at preventing hospitalization and death.
• Variants: Lab data suggest “quite effective” against the UK variant as well as the South African and Latin American variants.

AstraZeneca-University of Oxford

On November 23, AstraZeneca and the University of Oxford announced high-level results from an interim analysis of their COVID-19 vaccine, AZD1222. The analysis was from the trials in the UK and Brazil and demonstrated the efficacy of up to 90%. The vaccine was effective at preventing COVID-19, with no hospitalizations or severe cases in people receiving it. There were a total of 131 COVID-19 positive cases in the interim analysis group. One dosing regimen was given at a half dose and demonstrated 90% efficacy, followed by a full dose at least one month apart. Another dosing regimen demonstrated 62% efficacy when given two full doses at least one month apart. The combined analysis showed average efficacy of 70%. The AstraZeneca vaccine can be stored, transported, and handled at normal refrigerated conditions, about 36-46 degrees F for at least six months, and administered within existing healthcare settings.

On March 25, 2021, AstraZeneca released a primary analysis that the vaccine demonstrated 76% efficacy against symptomatic COVID-19, 100% efficacy against severe or critical disease and hospitalizations, and 85% efficacy against symptomatic COVID-19 in people 65 years and older.

The AstraZeneca and University of Oxford’s vaccine use technology from an Oxford spinout company, Vaccitech. It deploys a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees. It contains the genetic materials of the spike protein. After vaccination, the cells produce the spike protein, stimulating the immune system to attack the SARS-CoV-2 virus.

• Type: Adenovirus-based
• Doses: 2, 28 Days Apart
• Efficacy: Currently about 70% overall.
• Variants: At least one study finds it has little effect against the South African variant but appears effective against UK and Brazilian variants.

Russia’s Sputnik V Vaccine

Around November 11, Russia’s National Research Center for Epidemiology and Microbiology, which Russia authorized for use in August—ahead of even beginning a Phase III trial—claimed had an efficacy rate of 92% after the second dose. It was based on a first interim analysis 21 days after the first injection during the ongoing Phase III study. On November 24, the organization claimed 95% efficacy based on new preliminary data. On December 14, 2020, they reported an efficacy of 91.4%. It also offered to share one of its two human adenoviral vectors with AstraZeneca to increase the efficacy of the AstraZeneca vaccine.

Russia’s Gamaleya research institute appears to be focused on potentially marketing their vaccine worldwide. Even the name of the vaccine has emphasized the idea of a race. The organization has indicated a dose of the vaccine will cost no more than $10, about half the cost of the Pfizer vaccine. The organization has also predicted they could produce 1 billion doses in the next year. At this time, aside from Russia, it will potentially be sold in India, Korea, Brazil, China, and Hungary. The Hungarian government is the only European Union country to express interest to date.

On February 2, 2021, The Lancet published Phase III data demonstrating a 91.6% efficacy against the original strain of the virus.

• Type: Adenovirus-based
• Doses: 2
• Efficacy: 91.4%
• Variants: Unknown. Clinical trial data was largely conducted in Russia prior to the emergence of major variants.

Sinovac Biotech

On January 13, 2021, China-based Sinovac Biotech reported that its COVID-19 vaccine had a 50.38% efficacy in late-stage clinical trials in Brazil. The company’s clinical trials are demonstrating dramatically varying efficacy rates. In Indonesia, a local trial demonstrated an efficacy rate of 65%, but the trial had only 1,620 participants. Turkey reported an efficacy rate of 91.25% in December 2020. Another trial in Brazil run by a local partner, Butantan Institute, reported last week a 78% efficacy rate in mild cases while 100% against severe and moderate infections. It is an inactivated vaccine that uses inactivated SARS-CoV-2 viruses.

• Type: Inactivated SARS-CoV-2 virus
• Doses: 2
• Efficacy: 50.38% to 91.25%, depending on the clinical trial
• Variants: Unknown, although a study in Brazil demonstrated 50.4% efficacy at preventing symptomatic infections.

Bharat Biotech

On April 22, 2021, India’s Bharat Biotech reported interim data from the Phase III trial of its COVID-19 vaccine COVAXIN, which demonstrated a 100% efficacy against severe infection. The vaccine was developed with seed strains from the Indian Council of Medical Research’s (ICMR) National Institute of Virology. It is a highly purified and inactivated vaccine. A second interim analysis suggested a 78% efficacy against mild, moderate, and severe disease, and 70% efficacy against asymptomatic disease. Does not require sub-zero storage, no reconstitution requirement, and ready to use the liquid in multi-dose vials, stable at 2-8 degrees C.

• Type: Inactivated SARS-CoV-2 virus using Whole-Virion Inactivated Vero Cell platform technology.
• Doses: 2, 28 days apart
• Likely EUA Date: Not applicable in the U.S.
• Efficacy: 100% against severe infection; 78% against mild, moderate, and severe; 70% against asymptomatic
• Variants: Wildtype; can neutralize UK variant