Vaccines are a lot safer than they used to be in the old days.
No, I’m not talking about the “crude brew” that was the original DTP vaccine.
This older vaccine used more antigens than the DTaP vaccine that replaced it, so could cause more side effects. Even before that though, there was less oversight of vaccine manufacturers in the early 20th century. This could lead to vaccines that were contaminated or which simply didn’t work.
That certainly was a problem with the early smallpox vaccine, which is typically considered to be the most dangerous vaccine ever routinely used.
Variolation and Smallpox
But even before the smallpox vaccine was developed by Edward Jenner in 1796, we had variolation.
While the smallpox vaccine involved the cowpox virus, variolation actually infected someone with smallpox. The idea was to give the person a milder form by exposing them to a weaker, or attenuated, form of the virus.
They got this weakened virus from the smallpox scabs of someone who had already recovered and:
- blowing dried smallpox scabs into their nose
- applying pus from smallpox scabs to a small puncture wound on their skin
Variolation worked, giving the person immunity to smallpox – if they survived.
Unfortunately, about 1 to 3% of people who underwent variolation died.
And people who had recently undergone variolation could be contagious, leading to smallpox epidemics.
So why did folks undergo variolation if they had a chance of dying from the procedure?
It’s simple.
A natural smallpox infection was so much more deadly. Up to 30% of people who got smallpox died, and many people eventually got caught up in the regular smallpox epidemics that plagued people in the pre-vaccine era.
The Hospital Rock Engravings of Farmington, Connecticut
We don’t have to worry about smallpox anymore.
Well, not about natural smallpox infections, since smallpox was eradicated back in 1980.
And there are many other diseases that we get vaccinated against, with it being extremely easy to get that protection, especially compared to what folks did in the old days.
Do you know how far folks went to make variolation safer?
“Every year, thousands undergo this operation, and the French Ambassador says pleasantly, that they take the small-pox here by way of diversion, as they take the waters in other countries. There is no example of any one that has died in it, and you may believe I am well satisfied of the safety of this experiment, since I intend to try it on my dear little son. I am patriot enough to take the pains to bring this useful invention into fashion in England…”
Lady Mary Wortley Montagu On Small Pox in Turkey (1717)
They actually went to smallpox hospitals to get vaccinated, remaining in quarantine for up to three weeks so that they wouldn’t get others sick.
In Farmington, Connecticut, two doctors established the Todd-Wadsworth Smallpox Hospital and had a lot of success with variolation.
Patients were no longer starved before inoculation, and many had begun to doubt the efficacy and safety of vomiting, sweats, purges, mercurials (toxic mercury salts such as calomel), and bleeding which had previously weakened both inoculees and those who “took the pox in the natural way.”
Charles Leach, MD on Hospital Rock
There, up to 20 patients at a time stayed in quarantine to get variolated, as a smallpox epidemic hit nearby Boston.

Between 1792 and 1794, many who got variolated wrote their names on what is now known as Hospital Rock.
“Many have supposed that the names on this rock were those who had did of the small-pox, but this is a great mistake. Every name on the rock is that of a person who was living when the name was placed there. Norris Stanley lived to own ships which were captured in the war of 1812 by Algerian pirates and still later to receive from the United States an indeminity therefor amounting to a large sum.”
James Shepard on The Small Pox Hospital Rock
The nearby town of Durham seemed to go a different way.
Instead of an inoculation hospital, they had a pest house to quarantine folks with natural smallpox infections.
Adding to the history of smallpox in Connecticut – a smallpox burying ground in Guilford.
Why wasn’t variolation popular everywhere? Folks didn’t have to wait for the first vaccine for the anti-vaccine movement to get started.
What to Know About Smallpox and the Hospital Rock Engravings
Hundreds of people got safely inoculated against smallpox and left their names on Hospital Rock near Farmington, Connecticut just before Edward Jenner discovered the first smallpox vaccine.
More on the Hospital Rock Engravings
- Hospital Rock Engavings
- Hospital Rock
- The Small Pox Hospital Rock in the 1895 Connecticut Quarterly
- Hospital Rock A Landmark In Smallpox Battle
- The View/From Farmington; Etched in Stone, Smallpox Memories
- Variolation
- How Variolation Worked
- Cotton Mather, Onesimus, George Washington, and Variolation
- From Variolation to Cowpox Vaccination: The First Steps Towards Eradicating Smallpox
- The Fight Over Inoculation During the 1721 Boston Smallpox Epidemic
- The Story of Smallpox in Massachusetts
- Study – Addressing Parents’ Concerns: Do Multiple Vaccines Overwhelm or Weaken the Infant’s Immune System?
- CDC – Smallpox Vaccines
- WHO – Safety of smallpox vaccines
- The Most Dangerous Vaccine
- Book – Pox: An American History
- Book – Deadly Choices