I have always heard that European explorers brought smallpox to the western hemisphere. It seems unlikely to me that anyone with an active case of smallpox would have survived the voyage so there must have been latent carriers aboard.
It's interesting that smallpox showed up, not for the first time, in Boston during George Washington's time as general of the Continental Army. Having had smallpox himself and recovering from it from a time he had traveled to Barbados, he had an immunity that the majority of his troops did not have. The British on the other hand, had herd immunity as smallpox had been around in England and many soldiers had developed immunity because they were infected as children. I think it's interesting how Washington took steps that are similar to what is being recommended today with COVID.
Smallpox was spread similarly to COVID - droplets in the air from person to person. Camps were crowded and unsanitary. Washington quarantined those showing symptoms and kept outsiders away from his troops - same thing we do today. Still as new recruits came in they were exposed. The British also, reportedly, sent infected persons outside of Boston to infect revolutionaries.
Vaccinations (unlike todays vaccinations - not a needle) were around, but that meant that soldiers getting the shot would become ill with smallpox and George was afraid it would lead to an epidemic within his troops, so he stayed with quarantining which worked for awhile.
Eventually, as smallpox continued devastating the troops, George had the choice of continuing to quarantine soldiers, which he needed healthy, or vaccinate them - he ordered vaccinations to all soldiers who had never had smallpox. Similar to today, he was trying to reach herd immunity within the troops. Some historians consider the move to vaccinate his army and all new recruits a deciding factor in winning the war.
Of course today, smallpox is no longer around. Will that one day be a possibility with COVID? Maybe not, as has been discussed in many of the SB threads, but can we control it if people do their part?
Interesting stuff!! Maybe we need the ghost of George to order vaccinations, quarantines, wearing masks, etc.....