MYTH: COVID-19 vaccines were developed too quickly to be sure they’re safe and effective
FACT: COVID-19 vaccine development was able to advance quickly due to years of previous research on pandemic preparedness, coronaviruses, and vaccine delivery platforms
By: Richard Jefferys
Last updated: July 12, 2021
In the early days of the COVID-19 pandemic, there was considerable uncertainty about the possible timeline for development of an effective vaccine. Experts noted that vaccine development can be unpredictable, and that it typically takes at least several years to go through the process of designing a vaccine, testing it for safety and ability to induce immune responses, then finally conducting efficacy trials to assess whether it works to protect against an infection and/or disease.
The fact that this process was accomplished within a year for several COVID-19 vaccines has led to some suspicion that perhaps corners were cut and research moved too fast. There are several reasons why these suspicions are unfounded:
- The technologies used in the vaccines have been in development for many years (in some cases decades). For example, messenger RNA (mRNA) vaccines have been tested in therapeutic trials for people with HIV, and adenovirus vectors have also undergone large scale testing and are used in a licensed vaccine against Ebola infection.
- Most available COVID-19 vaccines deliver a component of the SARS-CoV-2 called the spike protein, which prior research on similar coronaviruses had shown to be a key target for immune responses (particularly the neutralizing antibody responses considered vital for protection). Researchers figured out the structure of the coronavirus spike protein back in 2016, and this allowed for the design of modified version specifically intended for inclusion in vaccines. The technique was first applied to the coronavirus that caused Middle East Respiratory Syndrome (MERS) in 2017. The authorized COVID-19 vaccines from Moderna, Pfizer/BioNTech, and Johnson & Johnson all include a modified “prefusion” version of the SARS-CoV-2 spike protein made possible by this prior pandemic preparedness research.
- The rapid completion of large-scale trials testing the efficacy of candidate COVID-19 vaccine was made possible by the fact that SARS-CoV-2 was spreading rapidly. The number of symptomatic COVID-19 cases among trial participants rose quickly and this meant that the ability of vaccines to protect against the disease became evident much more quickly than is typically the case in vaccine efficacy trials.
Importantly, monitoring of the safety of the vaccines continues even after authorization, allowing warnings and information about any potential rare side effects to be made publicly available. Vaccine manufacturing is also subject to careful regulation, and the issues identified at one contractor’s production facility for adenovirus-based products (which led to a large number of doses needing to be discarded) are evidence of this process in action. The issues were not caused by the rapidity with which COVID-19 vaccines were developed.