Table 1.

Fixed Input Parameters for Several Possible Scenarios in a Model of a Measles Outbreak in an Amish Community, Ohio, 2014

Parameter	Symbol	Formula	Value	Source
Transmission probability	β	R0/ND		N/A
Scenario 1a			2.74 × 10−5 contacts per day
Scenario 2b			6.12 ×10−5 contacts per day
Basic reproduction number	R0	R/s		N/A
Scenario 1			7.14
Scenario 2			16.0
Reproduction number of cases prior to initiation of control measures	R	N/A	4.22	Likelihood-based estimation procedure (8, 10)
Proportion of the population that is susceptible at outset	s	VCc (1 − VEd,e) + sUf,g (1 − VC)		N/A
Scenario 1			0.59
Scenario 2			0.26
Population size	N	S + E + I + R	32,630	Young Center for Anabaptist and Pietist Studies, Elizabethtown College (14)
Average preinfectious or latency period	N/A	N/A	10 days	CDC measles surveillance manual (16) and ACIP recommendations (12)
Average duration of infectiousness	D	N/A	9 days	CDC measles surveillance manual (16) and ACIP recommendations (12)
Infectiousness rate (proportion of exposed persons who become infectious)	σ	1/average preinfectious or latency period	0.1 persons per day	N/A
Recovery rate (proportion of infectious persons who become immune)	γ	1/average duration of infectiousness	0.1 persons per day	N/A

Abbreviations: ACIP, Advisory Committee on Immunization Practices; CDC, Centers for Disease Control and Prevention; MMR, measles-mumps-rubella; N/A, not applicable.

^a Assuming ≥1-dose MMR vaccine coverage of 14% to calculate s (lower bound)—from a coverage assessment in a subset of affected Amish families (5).

^b Assuming ≥1-dose MMR vaccine coverage of 68% to calculate s (upper bound)—from the literature (13).

^cV_C represents vaccine coverage (≥1 dose of MMR vaccine).

^dV_E represents vaccine effectiveness (median effectiveness of 1 dose of MMR vaccine).

^eV_E = 93% (12).

^fs_U represents the proportion of unvaccinated persons who are susceptible.

^g unvax.S = 67.5%—from a household transmission study conducted during the outbreak.