Answers are grounded in this paper and cite their sources.
David J. Sencer, H. Bruce Dull, Alexander D. Langmuir, Epidemiologic Basis for Eradication of Measles in 1967: A Statement by the Public Health Service, Public Health Reports (1896-1970), Vol. 82, No. 3 (Mar., 1967), pp. 253-256
No takes yet. Share an insight, caveat, or question.
Sencer et al. (1967) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: