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Behind the Science: what is an mRNA Vaccine?

Pfizer Vaccines
Pfizer UK

25th August 2020

Vaccines are considered one of the greatest developments of modern medicine, helping to nearly wipe out many infectious diseases.1 But creating and developing vaccines involves a long and complex process2 that remains a combination of art and science.


Researchers and scientists around the world are working to develop a potential COVID-19 vaccine. Given the urgency of the pandemic, strong partnership across the research and healthcare community is vital, using our scientific knowledge, people and resources to tackle the COVID-19 outbreak.

Pfizer is collaborating with German biotech company BioNTech to focus on a technology called an mRNA vaccine.3 Unlike conventional vaccines, which are produced using weakened forms of the virus,4 RNA vaccines can be constructed quickly using only the pathogen’s genetic code.5

Many standard vaccines work by injecting a dead or weakened form of the pathogen into the body in preparations that are designed not to make you sick but rather to build immunity. The key to building this immunity is that the portion of the pathogen called the antigen trains the immune system to recognise and respond to the infectious agent.5

RNA vaccines work by introducing into the body a messenger RNA (mRNA) sequence that contains the genetic instructions for the vaccinated person’s own cells to produce the vaccine antigens and generate an immune response.5

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We’re working in collaboration with German biotech company BioNTech on a COVID-19 development programme, focusing on mRNA vaccine technology. Learn more about mRNA vaccines.


  1. Hogan, M.J. et al. mRNA vaccines — a new era in vaccinology. Nat Rev Drug Discov. 2018 Apr; 17(4): 261–279. Available at: [Last accessed July 2020]
  2. IFPMA. The complex journey of a vaccine. Available at: [Last accessed July 2020]
  3. Pfizer press release. Available at: [Last accessed July 2020]
  4. NHS. Why vaccination is safe and important. Available at: [Last accessed July 2020]
  5. PHG Foundation. RNA vaccines: an introduction. Available at: [Last accessed July 2020]


PP-VAC-GBR-1541 / August 2020