1. Enhanced Varicella Outbreak Surveillance at West Virginia Public Schools
Maria del Rosario, MD, MPH
Arianna DeBarr, RN, BSN
Vaccine Preventable Disease Program
December 6, 2017

2. Objectives Review the epidemiology of varicella
Review West Virginia’s past experience with enhanced varicella outbreak surveillance in public schools
Describe the proposed plans for enhanced varicella outbreak surveillance in West Virginia public schools

3. Varicella (Chickenpox)
Etiologic agent
Caused by Varicella-zoster virus (VZV)
Clinical Presentation
Blister-like rash
Lesions (>200) in different stages
Itchy
Fever, malaise
Starts on stomach, back, and face spreading to body

4. Transmission Person-to-person by:
Respiratory route (breathing in aerosols)
Direct contact with virus particles
Infected person is infectious one to two days before the rash appears until all lesions form scabs (five to seven days)
Very contagious
Secondary attack rate in susceptible household contacts = 85% (61%-100%)

5. Complications Often seen among infants, adults, and immunocompromised
Bacterial infections
Pneumonia
Encephalitis
Hemorrhagic conditions

6. Breakthrough Varicella
Infection with wild-type varicella occurring >42 days after vaccination
Contagious
15%-20% of one-dose vaccinated persons exposed to VZV
Mild disease
<50 lesions
Low to no fever
Shorter rash duration
Fewer vesicles
Mostly maculopapular instead of vesicular
25%-30% of Breakthrough Varicella cases are not mild

7. Reportable Varicella

8. Reportable Varicella (cont’d)

9. Temporal Trend of Varicella

10. Vaccine Effectiveness Study
Background and Methods
Federally funded (American Recovery Reinvestment Act)
January 2010 to May 2011
Purpose: evaluate 2-dose varicella vaccine effectiveness (VE)
All West Virginia public schools (n=688)
Respondents: school nurses (n=220)
Case control = 1:3
Reference: PIDJ, November; 33 (11):

11. Vaccine Effectiveness Study (cont’d)
Results
Total cases = 133 cases, 365 controls
Vaccine effectiveness (VE) against ALL varicella:
Varicella vaccine VE
95% CI
One-dose
83.2%
69.2%
90.8%
Two-doses
93.9%
86.9%
97.1%
Two-doses vs. One-dose
63.6%*
32.6%
80.3%
*incremental VE

12. Vaccine Effectiveness Study (cont’d)
Results
Vaccine effectiveness (VE) in preventing moderate/severe varicella:
Breakthrough cases with one dose and two doses had milder rash compared with unvaccinated cases
Varicella vaccine VE
95% CI
One-dose
88.2%
72.7%
94.9%
Two-doses
97.5%
91.6%
99.2%
Two-doses vs. One-dose
78.6%
40.9%
92.3%

13. Outbreak and Vaccine Effectiveness Study
Background
2007: Two-dose varicella vaccine program adopted in United States to decrease disease and prevent outbreaks
Methods
Nine states’ (including West Virginia) health departments
Varicella outbreaks reported to Centers for Disease Control and Prevention (CDC),
Outbreak setting
Number of cases per outbreak
Vaccination status
Laboratory confirmation
Source: PIDJ, 2015 Oct; 34(10):

14. Outbreak and Vaccine Effectiveness (cont’d)
Findings
: 929 outbreaks reported
95% of outbreaks reported from schools
Decline in number of outbreaks by 78%
2005 = 147 outbreaks
2012 = 33 outbreaks
Decrease in size of outbreak
Median size = 12
Median size = 7
Decrease in duration of outbreak
Median duration = 38 days
Median duration = 26 days

15. Local Health Department
What
Where
When
How
Varicella aggregate counts
Through West Virginia Electronic Data Surveillance System (WVEDSS)
Weekly
WVEDSS - varicella reporting form
Varicella outbreaks
To the Department of Health & Human Resources, Division of Infectious Disease Epidemiology (DIDE)
Immediately after notified
Phone call to the on-call epidemiologist

16. West Virginia Public School Nurses
What
Where
When
How
Aggregate varicella counts
To Local Health Department (LHD)
Weekly
Via fax or phone call
Varicella outbreaks
To LHD
Immediately
Phone call
Survey on varicella outbreaks
Submit to DIDE
Monthly
SurveyMonkey
Excel spreadsheet with varicella case counts
Attached to

17. Excel Spreadsheet

18. State Health Department
What
Where
When
How
Send out survey
To West Virginia Public School Nurses
Monthly
Through
SurveyMonkey
Assess data from school nurses
Export to excel file
Assess varicella aggregate reporting
WVEDSS
Bi-Monthly
Excel file exported from WVEDSS
Provide feedback
Bi-Monthly to Regional Epidemiologists and LHDs
Monthly to school nurses

19. Varicella Aggregate Reporting Enhanced Varicella Surveillance
Varicella Reporting
Description
Varicella Aggregate Reporting
Enhanced Varicella Surveillance
Why it is required
West Virginia Reportable Disease Rule
Vaccine Preventable Diseases grant requirement
Target population
All healthcare providers, school nurses, healthcare facilities
All students (k-12) in West Virginia public schools
Who collects data
LHD Nurses
School Nurses
Frequency of data collection
Weekly
How data is submitted
Through the WVEDSS
Through SurveyMonkey with an excel spreadsheet attached
Frequency of reporting
Weekly - every Monday with previous week’s count
Weekly to LHD
Monthly to DIDE
Number of reports submitted
One report per county
One report per school

20. Purpose 2017-2018 Improve knowledge of the epidemiology of varicella
Assess virus transmission patterns
Describe disease burden and risk factors for severe varicella
Provide estimates of varicella vaccine effectiveness
Identify risk factors for the vaccine failure
Monitoring varicella outbreaks
Assess the impact of second-dose vaccine recommendation
Facilitate the development and refinement of appropriate public health interventions

21. Enhanced Varicella Survey

22. Enhanced Varicella Survey (cont’d)

23. Enhanced Varicella Survey (cont’d)

24. Enhanced Varicella Survey (cont’d)

25. Enhanced Varicella Survey (cont’d)

26. Enhanced Varicella Survey (cont’d)

27. Enhanced Varicella Survey (cont’d)

28. Contact
Arianna DeBarr, BSN, RN Vaccine Preventable Disease Nurse West Virginia Department of Health and Human Resources Bureau for Public Health Office of Epidemiology and Prevention Services Division of Infectious Disease Epidemiology Phone: (304) Fax: (304)
Here is my contact information and for more information on AFM please visit our website at

29. Contact
Maria del Rosario, MD, MPH Director of Surveillance West Virginia Department of Health and Human Resources Bureau for Public Health Office of Epidemiology and Prevention Services Division of Infectious Disease Epidemiology Phone: (304) Fax: (304)
Here is my contact information and for more information on AFM please visit our website at