General questions

How could vaccines be developed at record speed while still maintaining quality and safety?


Before authorization, all vaccines have to go through preclinical and three phases of clinical trials. Although the vaccines are developed at record speed, no compromise is made on ensuring their safety and efficacy.

The following three things have made it possible for the vaccines to be developed so quickly while still being high quality and safe:

  • First, by building on scientific and technological progress: Investments in new technologies over the last few years have made it possible for many labs around the world to work with new vaccine platforms, such as mRNA, for other infections. As soon as the necessary information about the virus that causes COVID-19 was available, scientists began designing the mRNA instructions which would allow the host cells to build the unique spike protein of SARS-CoV-2 into an mRNA vaccine.
  • Second, by optimizing development and regulatory processes: by conducting trials in parallel rather than sequentially; by early communication and alignment on trial design; by exploring flexibilities such as regulatory review of data on a rolling basis (as soon as they are made available); by promoting regulatory reliance on generated evidence through collaborative approaches, transparency and sharing of information. This way, timelines for development were accelerated for these vaccines by overlapping phases one and two of clinical trials. Regulatory approval was accelerated by ensuring that regulatory agencies were ready and flexible to review each phase quickly so, if all went well, they could approve each next step soon after data from the previous step became available. Sharing of information among regulatory authorities is common practice and this also helps improve and speed up the regulatory process.
  • And third, by investing in manufacturing despite the financial risk: Investments were made well before the end of the clinical trials so that it was possible to have millions of doses ready to deploy if the vaccine was licensed.

Rapid development of safe and effective vaccines made possible by:

  • new technologies
  • parallel clinical trial phases
  • rolling regulatory reviews, collaboration and reliance
  • up front investments in manufacturing

COVID-19 vaccines and vaccination explained – Introduction


Vaccines protect against severe COVID-19 disease.


Why are some vaccinated people also hospitalized with COVID-19?


How could vaccines be developed at record speed while still maintaining quality and safety?


What are clinical trials and are they enough to prove a vaccine is safe?


How do mRNA vaccines, like Pfizer-BioNTech and Moderna COVID-19 vaccines, work?


How do vector vaccines work?


How should we respond to claims that the mRNA vaccines could cause a genetic change and that we will see this in the coming decades?


How do inactivated vaccines work?


How do protein-based vaccines work?


How do I know which COVID-19 vaccine to choose or recommend?


What tests or examinations should people get before COVID-19 vaccination?


Can a new variant of the SARS-CoV-2 virus cause more severe disease?


Why should older adults get vaccinated?


Omicron is generally less severe than previous variants – does it still make sense to vaccinate children?


Should children aged 5-11 get a booster dose?


If COVID-19 becomes endemic will vaccination still be needed?


Why is it necessary to stay in the healthcare facility 15-30 minutes following COVID-19 vaccination?


Is it possible to catch COVID-19 during an immunization visit to a healthcare facility?


What are the so-called COVID-19 bivalent booster vaccines?


What is the recommended use of updated bivalent COVID-19 booster vaccines?


How do the updated bivalent COVID-19 vaccines work?