1. Department of Biostatistics & Epidemiology, College of Public Health, East Tennessee State University, Johnson City, TN 37614, USA
2. Center for Rural Health Research, College of Public Health, East Tennessee State University, Johnson City, TN 37604, USA
3. Surveillance Systems and Informatics Program (SSIP), Communicable & Environmental Disease & Emergency Preparedness (CEDEP), Tennessee Department of Health, Nashville, TN 37243, USA
4. Vaccine-Preventable Diseases & Immunization Program (VPDIP), Communicable & Environmental Disease & Emergency Preparedness (CEDEP), Tennessee Department of Health, Nashville, TN 37243, USA