The earliest notes on the reproduction number in relation to herd immunity: Theophil Lotz and smallpox vaccination.
Nishiura
Hiroshi
H
Dietz
Klaus
K
Eichner
Martin
M
D004813:Epidemiology / Q000266:history; D049672:History, 19th Century; D006801:Humans; D032521:Immunity, Herd; D012899:Smallpox / Q000266:history*; D012900:Smallpox Vaccine / Q000266:history*; D013557:Switzerland; D014611:Vaccination / Q000266:history
D012900:Smallpox Vaccine