The smallpox virus raged among humans for 10,000 years before a leap of insight led to the vaccine that killed it forever. The insight took about 300 years to develop.
Today, in the wake of the Covid crisis, drug companies throughout the world are experimenting with vaccines. One company, Moderna, took 42 days to create an experimental vaccine.
Why so fast?
The most obvious reason is the research infrastructure: Laboratories, drug companies, medical systems — systems we take for granted — have never before been available on such a wide scale. Humans are in the era of science and technology.
Still, of the seven known coronaviruses, there are no known human vaccines.
According to Johns Hopkins Senior Scholar Dr. Amesh A. Adalja, the key to the new rapid development of vaccines is new vaccine platform technologies. Writing in leapsmag.com, Adalja says these platforms use the same building blocks to make more than one vaccine. Using the basic platform, researchers are able to, in effect, switch out one targeted virus (or bacteria or other organism) like a person switches out a video game cartridge. One example of that is the ebola vaccine, which uses another virus as a platform with the ebola protein inserted.
A variety of different approaches are being used to create a Covid vaccine. Moderna is using an RNA approach. Inovio is using a DNA model in which genetic material is injected into the platform and human cells translate it into a viral protein. At that point the immune system makes antibodies.
Other approaches include nanoparticles (by Novavax), while other companies try to adapt an avian coronavirus vaccine.
According to Adalja, a coronavirus vaccine could possibly confer protection against other human coronaviruses, eliminating their use as a biological threat in the future.
And, even curing the common cold.

As bad as Covid-19 has been, it is not even close to the worst viral disease that has swept humanity.
That honor probably goes to smallpox, a disease so toxic that it wiped out entire populations, killing up to 500 million people in the 20th century alone. It was especially deadly for children, killing up to 80 percent. Survivors of any age were left disfigured, blind, or both. After exposure, symptoms began within a week to 19 days. High fever, fatigue, aches, and vomiting appeared first, followed by red sores on the face, hands, arms, and, finally, trunk of the body. These sores left deep, pitted scars on survivors.
According to estimates by the Centers for Disease Control, the Covid virus kills between 0.26 percent and 0.4 percent of infected people. Smallpox killed no less than 20 percent and up to 60 percent in some populations.
According to the Annals of Internal Medicine, the earliest written accounts were from China in about 400 BC, but possibly earlier.

The good news
Today smallpox is gone. The last case in the U.S. was in 1949 and the last case in the world was in 1978. Today the only remnants of smallpox are the light scars left by vaccinations on people born before the 1980s. In 1979, it was declared eradicated after massive inoculation campaigns on every continent. It is thought to live only as a sample in three labs in the world.

First vaccinations
For more than a thousand years, people knew that once a person contracted smallpox, they would ever after be immune. This knowledge led to the first genuine vaccinations.
In China, as early as 400 BC, smallpox scabs were ground up and injected into the noses of healthy people.
The first western experimentation was in 1789 by English doctor Edward Jenner, who found that a similar virus, cowpox, could protect humans. The technique, which used fluid from an active smallpox sore, was scratched into the skin or vein.
The technique was not perfect. People contracted a fever and perhaps some sores but recovered. However, there was a risk of contracting the active disease.