How Was the COVID-19 Vaccine Developed?

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Editor’s Note: If you’re looking for the latest on the vaccine rollout, vaccine boosters and other developing stories related to vaccination, please visit our Everything We Know About the COVID-19 Vaccine breakdown.  To learn more about the changing circumstances regarding COVID-19, be sure to check the CDC website.

In the midst of the United States reporting some of its highest daily case numbers since the pandemic began, pharmaceutical company Pfizer announced that its vaccine candidate was found to be more than 90% effective in preventing COVID-19 infections among people who hadn't previously contracted the virus. Just weeks later, in mid-November, two more pharmaceutical companies — Moderna and AstraZeneca — reported that Phase 3 testing and preliminary analyses had found their vaccine candidates to be 94.5% and up to 90% effective, respectively. The vaccine made by Johnson & Johnson/Janssen Pharmaceuticals also received clearance for distribution and was found to be 66.3% effective at preventing the virus during trials.

Now, after applications for Emergency Use Authorization were approved by the U.S. Food and Drug Administration (FDA) in December of 2020, vaccines from Pfizer and Moderna are currently being distributed across the country and administered to most members of the U.S. population. The Johnson & Johnson vaccine's distribution has also resumed following a temporary halt in early April after the CDC and FDA's vaccine reporting system found that multiple people had developed a rare blood-clotting disorder upon receiving their dose. While this news is concerning, the overall widespread distribution of vaccines is a huge leap forward for mitigating the spread of the disease — especially considering previous estimates that indicated a vaccine might not be ready until late 2021.

While it’s clear we won’t be "going back to normal" post-pandemic, a widely available COVID-19 vaccine will certainly help us regain some sense of normalcy, particularly when it comes to sharing public spaces safely and as more and more people obtain the two vaccine doses needed for immunity. So, how were the COVID-19 vaccines developed and how, exactly, do they combat the virus?