mRNA Vaccines Against COVID-19 Are Authorized

In March 2020, researchers began some of the first clinical trials of vaccines against SARS-CoV-2, the pathogen responsible for the COVID-19 pandemic. Prior to this global crisis, creating an immunization against an infectious disease routinely spanned several years, and no preventive shot existed for any coronavirus affecting humans. Traditional vaccines based on killed or weakened viruses, viral proteins, or harmless carrier viruses required large-scale cell culture, a resource-intensive process that limited rapid production during outbreaks. Confronting a rapidly spreading pathogen, scientists and regulators modified conventional development pipelines by running standard trial phases in parallel rather than sequentially, compressing an extensive evaluation cycle into mere months.

The unprecedented speed of this response rested on groundwork established well before the outbreak. Previous scientific efforts had targeted earlier human coronaviruses, severe acute respiratory syndrome and Middle East respiratory syndrome, which provided valuable structural templates. Messenger RNA technology in particular had advanced over decades through fundamental laboratory investigations by scientists Drew Weissman and Katalin Karikó. By 2010 several companies were developing mRNA vaccines, including candidates against Zika virus and MERS, while vector-based vaccines were already in use against the Ebola virus.