The vaccine was developed in a much shorter period of time, due to the obvious need to address the public health threat the pandemic posed to the nation. A shorter development and review time does not mean the vaccine is unsafe.

Scientists had a head start: COVID-19 vaccines are built on years of work to develop vaccines for similar viruses. All available vaccines use technologies that researchers have been studying and working with for decades – which included technology advances to map the virus’s DNA. A lot of the groundwork was already laid during the search for vaccines to fight Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS).

The Coronavirus that causes COVID-19 is part of a broader family of coronaviruses – and related to SARS and MERS. Researches have been engaged in searching for vaccines for those closely related viruses for several years, so they were not starting from scratch with COVID, according to the Mayo Clinic. Researchers also benefited from a budget of $4.5 billion from the US government, which gave vaccine manufacturers all the resources they needed to accelerate their process.

Additionally, the clinical trial process was accelerated by enrolling more people in trials to enhance rapid data collection and earlier analysis of safety data for demographically diverse populations. This also sped up the FDA review process as they have been monitoring the data all along. 

And, delivery/distribution time was shortened by allowing manufacturing to occur at the same time as instead of after, vaccine approval.