"In 1779, an outbreak of smallpox among sailors of a
powerful French and Spanish armada in the English Channel
saved England from perhaps the most serious danger of
invasion it has ever faced, at a time when most of the British
Navy was engaged on the opposite side of the Atlantic, in
North America."
Smallpox: Ten Years Gone
DONALD R. HOPKINS, MD, MPH
https://ajph.aphapublications.org/doi/pdf/10.2105/AJPH.78.12.1589
There was no pest house in Williamsburg in which to send our patients suffering from the smallpox, but an announcement in the March 5, 1779 issue of Dixon's Gazette advertised that on March 10 of that year, Doctor Gardiner's Hospital for the Smallpox would be opened in King and Queen County, Stratton Major Parish.
"Much of what happened in Williamsburg before the time of the vaccination was synonymous with what happened elsewhere [in Virginia]. Ten percent of the population usually died during epidemic, but in Williamsburg the mortality rate was low— 0.71%. Like most outbreaks, the one in 1747 occurred during the winter with a high fatality rate among children (15) and the elderly (7)".49
Edward Jenner's experiments on cowpox, a non-fatal, non-contagious disease, as a possible substitute for the smallpox virus in the inoculation, the subsequent vaccination proved to be much more of a success in the prevention of smallpox.
SMALLPOX IN THE 18th CENTURY
Susan Pryor, 1984
Research Report
Colonial Williamsburg Foundation - 0201