In 1928, Dr Alexander Fleming, a Scottish physician and scientist, accidentally discovered a substance with antibacterial properties produced by a mold called Penicillium notatum. He called it penicillin. For more than a decade after Dr Fleming published his findings in the British Journal of Experimental Pathology in 1929, the discovery that would become one of the greatest medical advancements of the 20th century met with little scientific interest.

Then World War II came along. Working with researchers from Oxford University in England who purified penicillin in 1939 and used it clinically for the first time in 1941, the United States — motivated to find a more effective treatment for wounds and illnesses in soldiers serving in the war — led a coordinated effort involving many scientists and multiple pharmaceutical companies to mass produce penicillin.1,2 The effort brought penicillin out of the laboratory and into widespread clinical use, ushering in a new era in the treatment of infectious diseases.

Nearly three-quarters of a century later, urgency once again provided an impetus to turn research into clinical reality. This time, the motivation is a pandemic rather than a war. A desperate need for a vaccine to prevent infection with SARS-CoV-2, the novel coronavirus that causes COVID-19, catapulted messenger RNA (mRNA) vaccine technology from the laboratory into primetime. In less than a year, the pharmaceutical companies Pfizer/BioNtech and Moderna, under contract with the US government as part of its “Operation Warp Speed,” translated investigational technology into COVID-19 mRNA vaccines and completed clinical trials that led to emergency use authorizations from the Food and Drug Administration. A stunning achievement.

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If mRNA vaccines bring an end to the pandemic and demonstrate long-term safety and efficacy, they may bring about a new era in infectious disease prevention. Researchers and pharmaceutical companies may be encouraged to develop mRNA vaccines to prevent many other illnesses, including those for which development of traditional vaccines has been elusive, such as HIV. Using mRNA technology, vaccines can be produced more rapidly than conventional vaccines, which typically use weakened or killed pathogens to induce an immune response.3 In addition, because of the way mRNA vaccines work, there is no danger of recipients contracting the disease the vaccines are designed to prevent.3

The COVID-19 virus likely will not be the last pathogen to cause a pandemic. If the COVID-19 mRNA vaccines fulfill their promise, governments and pharmaceutical companies will at least have a proven technology to address future emerging outbreaks.


  1. Gaynes R. The discovery of penicillin—New insights after more than 75 years of clinical use. Emerg Infect Dis. 2017;23(5):849-853. doi:10.3201/eid2305.161556
  2. Quinn R. Rethinking antibiotic research and development: World War II and the penicillin collaborative. Am J Public Health. 2013;103:426-434. doi:10.2105/AJPH.2012.300693
  3. Centers for Disease Control and Prevention. Understanding mRNA COVID-19 vaccines. CDC website. Accessed January 20, 2021.