In 1968, an “informal group of virologists” submitted a manuscript to the journal Nature. In that article, they described a novel group of viruses isolated from different animals and from humans. They suggested the viruses be named “coronaviruses” because their surface resembled the uppermost layer of the Sun, the “corona.” (“Corona” is also Spanish for “crown,” with roots in Latin.) Since that first discovery, coronaviruses have been identified in many species of animals, and they have been linked to different illnesses, most of them respiratory.
Among humans, four coronaviruses (HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1) are known to cause cold-like respiratory illnesses. In 2002, a fifth human coronavirus -- known as SARS CoV because it caused a “severe acute respiratory syndrome” -- triggered an epidemic that spread from Southeast Asia to different parts of the globe, including Europe, North America, Australia and Africa. In 2013, a sixth human coronavirus -- known as MERS because it caused the Middle Eastern respiratory syndrome -- triggered an epidemic of respiratory disease, with cases identified in the Middle East, Northern Africa, Asia, and the United States.
A seventh human coronavirus -- known as SARS CoV-2 -- was identified in China in 2019. The city of Wuhan in the Hubei Province saw a spike in respiratory disease cases. The disease was given the designation COVID-19 for “coronavirus disease 2019.” Unlike the previous five known human coronaviruses, SARS CoV-2 would set off a pandemic, with millions of cases and deaths worldwide. No country on the planet has been spared from the effects of the pandemic.
In 2020, with the pandemic fully underway, world governments raced to create vaccines as countermeasures. In August 2020, the government of Russia announced it had fast-tracked the creation of a vaccine, named Sputnik V. Between April and July 2020, Sinovac Biotech Ltd., a Chinese biotech company, launched clinical trials of an inactivated virus vaccine, named Coronavac. Around the same time, clinical trials of two novel vaccines (made by biotech companies Moderna and Pfizer-BioNTech) began in the United States. Those vaccines were based on decades-old technology, where messenger RNA (mRNA) would be used to deliver a message to immune cells to create their own version of a protein that looks like the proteins on the surface of the virus. This would allow vaccines to be created without the need to grow the virus in a laboratory. All that would be needed is the genetic code for the virus’ proteins.
In December 2020, the United States Food and Drug Administration authorized two mRNA vaccines for emergency use. In February 2021, a viral vector vaccine made by Johnson & Johnson Janssen was also authorized for emergency use. The Janssen vaccine delivers a DNA template of the spike protein to immune cells inside an inactivated adenovirus, triggering the recipient immune cells to create proteins, much in the same way that the vaccines made by Moderna and Pfizer-BioNTech do.
Other vaccines have been in development against SARS CoV-2. The New York Times has a great vaccine tracker on their website. The online tool keeps track of the progress in research and clinical trials of numerous vaccines around the world. For example, a French vaccine has been abandoned, and so has a Kazakhstani vaccine. As of April 15, 2022, the tracking tool shows 19 vaccines authorized for emergency use and 12 given full approval for use. Unfortunately, many countries around the world are unable to develop or produce their own vaccines, and many are too poor to afford acquiring vaccines for their populations.
Vaccines are not the only countermeasures used against the COVID-19 pandemic. National, state, and local governments mandated social distancing, quarantine of people exposed, and isolation of people who test positive for SARS CoV-2 infection. Many governments recommended and/or mandated the use of facial masks to prevent the transmission of the virus. Some societies accepted these mandates better than others. The Food and Drug Administration has also authorized — and experts have recommended — several drugs as therapeutics.
NOTE: A previous version of this article stated the Janssen vaccine delivered mRNA to cells. This has been corrected to mention that the vaccine delivers a gene instead of mRNA.