From the Guidelines
The Pfizer-BioNTech COVID-19 vaccine (Comirnaty) has a relative risk reduction of approximately 95% in preventing COVID-19, as demonstrated in its initial clinical trials 1. This means that vaccinated individuals had about 95% lower risk of developing COVID-19 compared to unvaccinated individuals. The vaccine contains mRNA that instructs cells to produce the SARS-CoV-2 spike protein, triggering an immune response that helps protect against future infection. Key points about the vaccine include:
- Efficacy: 95% protection against COVID-19
- Vaccination schedule: 2 doses, 21 days apart
- Safety profile: excellent, with common solicited adverse reactions including injection site reactions, fatigue, headache, muscle pain, chills, joint pain, and fever
- Serious adverse events: similar in the vaccine and placebo groups (0.6% and 0.5%, respectively) The high relative risk reduction made the Pfizer vaccine one of the most effective COVID-19 vaccines available, as supported by the data from the clinical trials 1.
From the Research
Relative Risk Reduction of Pfizer COVID-19 Vaccine
- The relative risk reduction of the Pfizer (Comirnaty) COVID-19 vaccine is reported to range from 45% to 96% across different studies 2.
- A study published in MMWR found that the effectiveness of full vaccination in preventing COVID-19-associated hospitalization was 96% for Pfizer-BioNTech among adults aged 65-74 years, and 91% among adults aged ≥75 years 3.
- Another study published in MMWR found that the effectiveness of 2 doses of Pfizer-BioNTech vaccine against COVID-19 hospitalization was 93% among children and adolescents aged 12-18 years 4.
- A systematic review published in Human vaccines & immunotherapeutics found that the full-dose regimen of the Pfizer/BioNTech vaccine is the most effective against infections with the B.1.1.7 and B.1.351 variants 5.
- A large observational study in Israel found that the Pfizer-BioNTech vaccine was effective in preventing infection, hospitalization, and mortality, with adjusted vaccine efficacy of 93·0%, 93·4%, and 91·1%, respectively 6.