Table 3.

Key Variables and Sources of Information for Participants

	Self-reported		Electronic Medical Records		Time Period
	Enrollment survey	EOS survey	EMR	Employee Records	From year(s) prior to the study	Data from years enrolled in study
Demographic
Sex					✓
Date of birth					✓
Marital status	✓		✓			✓
Country of birth			✓		✓
Immigration date			✓		✓
Ethnicity by country of birth of individual, the parents, or grandparents			✓		✓
Socio-economic status by clinic address			✓		✓	✓
Supplementary insurance status			✓		✓
Dates enrolled as CHS member			✓		✓
Level of education	✓					✓
Household composition (number of rooms; number of family members in the house)	✓					✓
Occupation and work responsibilities	✓				✓	✓
Family income	✓					✓
Health Status and Risk Behaviors
Health status and health behaviors	✓	✓			✓
Smoking status, history			✓		✓
Pack years			✓		✓
Height			✓		✓
Weight			✓		✓
Body mass index			✓		✓
Medication use for chronic conditions and immunosuppressants			✓		✓
Attitudes
Perceptions of illness, vaccines, missing work	✓					✓
Recollection of influenza vaccination (for vaccinated HCP)		✓				✓
Reasons for not receiving the influenza vaccine (for unvaccinated HCP)		✓				✓
Job satisfaction	✓					✓
Influenza Vaccination Documentation
Vaccine administration date			✓		✓	✓
Vaccine type			✓		✓	✓
Vaccine manufacturer & lot			✓		✓	✓
Employee Records of Illness Absences				✓		✓
Acute Respiratory Illness
Number of inpatient admissions associated with acute illness			✓		✓	✓
Chronic Medical Conditions and Pregnancy
Number of ambulatory or inpatient medical encounters associated with chronic medical condition			✓		✓	✓
Chronic medical conditions			✓		✓
Pregnancy					✓	✓

Abbreviations: EOS end of season, EMR electronic medical record, CHS Clalit health plan, HCP healthcare personnel