Given that we’re still in the middle of a global disease pandemic and we’ve been hearing about vaccines, especially the COVID-19 vaccines, almost daily, you might think that never before have vaccines been such a topic of discussion. However, while it might seem like vaccines are a miracle of modern medicine, they’ve actually been around for quite some time. Did you know that the idea of protecting people from deadly diseases by exposing them to that same disease has been around for over 500 years? It’s true! In the 1500s the Chinese described exposing people to smallpox to protect them. Specifically, they would take the scabs of infected individuals, grind those up, and use that material to expose healthy individuals. It was not 100% effective, but it does show us that even before we understood how cells, bacteria, viruses, and immunity actually work, some curious and courageous people seemed to understand that we could gain protection from exposure to infectious agents.
Smallpox continued to decimate human populations until the late 20th century. In fact, in the 200 years before we eradicated—or got rid of—smallpox, it killed over 500 million people. It’s impossible to know the true death toll before countries started recording deaths, but over the centuries it’s likely that hundreds of millions more died from smallpox.
It was a terrible disease with around 30% of cases ending in death. An important turning point in unlocking the power of vaccines was in 1796. A physician named Edward Jenner had an idea that exposure to a similar but different disease, called cowpox, might protect humans from smallpox. Jenner was right: it worked! What followed throughout the 1800s were increasingly bold steps by governments to help protect people from smallpox. In 1813 Congress established a National Vaccine Agency and required the US Postal Service to deliver the vaccine for free. Later, in 1874, Germany made it mandatory that everyone vaccinate against smallpox, and in the 1920s in America many schools required the vaccination before students could come to school. Sound familiar?
We finally saw the last case of smallpox in 1977 and in 1980 the World Health Organization declared the disease eradicated. It remains the only infectious disease to have that status, but many other vaccines have significantly reduced the harm from other diseases. The Centers for Disease Control actually has a list of fourteen diseases you probably have forgotten about, thanks to vaccines, including polio, rubella, and whooping cough. Most of them were never as deadly as smallpox, but they still caused enormous suffering throughout the world—often among children—until vaccines to protect against them were developed.
The mid-20th century saw the first modern “clinical trial,” which is a powerful way to test vaccines and other treatments and understand if they 1) actually work and 2) are safe. It tested a treatment for tuberculosis and used randomization and double-blinding, both of which are now standard features of clinical trials because they do so much to minimize error and other factors that might interfere with the outcomes.
The testing of COVID vaccines followed those same principles to ensure they are safe. As such, we now have safe and effective vaccines against COVID-19 and countless other diseases, demonstrating the real power of vaccines to protect us.
With a PhD in Exercise Physiology, Jonathan Dugas spends his days thinking about how we can help more people be more active. With four Ironman finishes and 13 marathons and counting, he’ll see you out on the road.