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Thein Shwe, VPD Epidemiologist Jeannie Shifflett, RN, Varicella Surveillance Nurse

Varicella Outbreak Investigation and Varicella Vaccine Effectiveness Assessment through Outbreak Investigation in Schools. Thein Shwe, VPD Epidemiologist Jeannie Shifflett, RN, Varicella Surveillance Nurse Stephen Frame, BS, Varicella Project Coordinator. Objectives.

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Thein Shwe, VPD Epidemiologist Jeannie Shifflett, RN, Varicella Surveillance Nurse

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  1. Varicella Outbreak Investigationand Varicella Vaccine Effectiveness Assessment through Outbreak Investigation in Schools Thein Shwe, VPD Epidemiologist Jeannie Shifflett, RN, Varicella Surveillance Nurse Stephen Frame, BS, Varicella Project Coordinator

  2. Objectives • To describe clinical description, diagnosis and epidemiology of varicella (chicken pox) • To discuss varicella surveillance in West Virginia • To understand investigation of an outbreak of varicella • To review West Virginia varicella surveillance data including varicella outbreaks • To discuss CDC varicella vaccine effectiveness project in school systems WVDHHR-BPH-DIDE

  3. Disease Description • Primary infection – varicella (chickenpox) • A generalized, pruritic (itchy), vesicular (raised blistery) rash • Mild fever, and • Other systemic symptoms • Tends to be more severe in adolescents and adults than in younger children • Breakthrough chickenpox • Mild and occurred in immunized children WVDHHR-BPH-DIDE

  4. Epidemiology of Varicella • Agent: Varicella zoster virus (member of herpesvirus family) – highly contagious • Host: humans – the only source of infection • Mode of transmission: • Contact with the mucosa of the upper respiratory tract or the conjunctiva • Person to person: direct contact, airborne droplets, or infected respiratory tract secretions, from contact with vesicular zoster lesions • Transplacental passage of virus from mother to the fetus WVDHHR-BPH-DIDE

  5. Epidemiology of Varicella cont. • Incubation period: 14-16 days (range 10-21 days) • Infectious period: 1-2 days before the rash to crusting of all lesions • Secondary infection (household contacts): 61-100% • Healthcare associated transmission in pediatric units • Immunity - lifelong • In temperate climates • Childhood disease • A marked seasonal distribution • Peak incidence - during late winter and early spring WVDHHR-BPH-DIDE

  6. Disease Burden • Prevaccine Era in U. S. • ~ 4 million cases of varicella • 10,500-13,000 hospitalizations (range 8,000-18,000) • 100-150 deaths each year • Mainly children - ~90% before the age of 15 years • 1970s-1980s • Highest rate – children 5-9 years of age • 1990s – highest rate – preschool age group WVDHHR-BPH-DIDE

  7. Specimen collection video http://www.cdc.gov/vaccines/vpd-vac/varicella/ WVDHHR-BPH-DIDE

  8. Diagnostic Tests for Varicella-Zoster Virus (VZV) Infection WVDHHR-BPH-DIDE

  9. Varicella Vaccination in the U. S. WVDHHR-BPH-DIDE

  10. Varicella Surveillance in West Virginia

  11. Varicella Surveillance (WV Communicable Disease Rule 64CSR7) • Weekly aggregate total • Healthcare providers to local health department • LHD to WVDHHR by using ILI and Chickenpox form • Varicella outbreak • Immediately reportable from healthcare provider to LHD WVDHHR-BPH-DIDE

  12. Varicella Case Definition (2010)http://www.cdc.gov/ncphi/disss/nndss/casedef/varicella_current.htm • Clinical description • An illness with acute onset of diffuse (generalized) maculo-papulovesicular rash without other apparent cause. • Laboratory criteria for diagnosis • Isolation of varicella virus from a clinical specimen, or • Varicella antigen detected by direct fluorescent antibody test, or • Varicella-specific nucleic acid detected by polymerase chain reaction (PCR), or • Significant rise in serum anti-varicella immunoglobulin G (IgG) antibody level by any standard serologic assay. WVDHHR-BPH-DIDE

  13. Varicella Case Definition 2010http://www.cdc.gov/ncphi/disss/nndss/casedef/varicella_current.htm • Case Classification • Probable: An acute illness with • Diffuse (generalized) maculopapulovesicular rash, AND • Lack of laboratory confirmation, AND • Lack of epidemiologic linkage to another probable or confirmed case. • Confirmed: An acute illness with diffuse (generalized) maculopapulovesicular rash, AND • Epidemiologic linkage to another probable or confirmed case, OR • Laboratory confirmation by any of the following: • Isolation of varicella virus from a clinical specimen, OR • Varicella antigen detected by direct fluorescent antibody test, OR • Varicella-specific nucleic acid detected by polymerase chain reaction (PCR), OR • Significant rise in serum anti-varicella immunoglobulin G (IgG) antibody level by any standard serologic assay. WVDHHR-BPH-DIDE

  14. WVDHHR-BPH-DIDE

  15. WVDHHR-BPH-DIDE

  16. WVDHHR-BPH-DIDE

  17. When you have an Outbreak of Varicella.. 12/2009 to 12/2011 Notify Varicella Team Immediately for Assistance at (304)558-5358

  18. Conduct a Preliminary Investigation • Why? - • To determine if varicella is the likely cause (verify the diagnosis) • To identify cases and the population at risk • To determine the magnitude of the outbreak • To implement control measures WVDHHR-BPH-DIDE

  19. Verify the Diagnosis • Know the case definition of varicella • Know the case definition of varicella outbreak WVDHHR-BPH-DIDE

  20. Know the Varicella Outbreak Case Definition(For the purpose of varicella vaccine effectiveness project from 12/09 to 12/11) • Three (3) cases or more from any facility such as a school or a day care center or a long term care facility, within one incubation period (21 days) WVDHHR-BPH-DIDE

  21. School “A” Varicella Outbreak Case 1 1-1-10 Case 3 1-31-10 Case 5 2-25-10 Case 2 1-24-10 Case 4 2-5-10 Do any of these cases make up an outbreak? If so, which of the cases make the outbreak? WVDHHR-BPH-DIDE

  22. Identify Cases and Contacts.. • Work with the facility’s healthcare personnel and/or administrator • Collect information • Create a line list • Name and demographic information • Vaccination information • Clinical information • Laboratory diagnosis if done WVDHHR-BPH-DIDE

  23. Line listing formhttp://www.wvdhhr.org/idep/pdfs/idep/varicella/Chickenpox_outbreak_line_listing.pdf WVDHHR-BPH-DIDE

  24. Alert Providers and Notify the Parents… • Send health alert letter and provider information sheet to HCPs • Send Parent/Guardian Notification Letter and public information sheet to parents/guardian or general public WVDHHR-BPH-DIDE

  25. Control the Outbreak • Isolate(exclude) or cohort: • Who: all infected persons with varicella or zoster • How long: until the rash has crusted WVDHHR-BPH-DIDE

  26. Follow up & Reporting • Check in with the facility for the status of the outbreak control • Document and update your regional epidemiologist and DIDE when the outbreak is controlled completely • Forward completed linelisting form with lab reports if availiable, and other reports to DIDE via Fax: 304-558-8736 WVDHHR-BPH-DIDE

  27. Benefits of Investigating a Varicella Outbreak • Understand vaccine failure or failure to vaccinate • Provide estimates of vaccine effectiveness in different outbreak settings • May identify risk factors for vaccine failure WVDHHR-BPH-DIDE

  28. WVDHHR-BPH-DIDE

  29. 2007-2009 Varicella OutbreaksN=19 WVDHHR-BPH-DIDE

  30. WVDHHR-BPH-DIDE

  31. WVDHHR-BPH-DIDE

  32. Lessons learned from Outbreak Investigation • Incomplete data • Low vaccination of varicella among exposed population • Outbreaks occurred among vaccinated population WVDHHR-BPH-DIDE

  33. Assessment of Varicella Vaccination Effectiveness through Outbreak Investigation in Schools WVDHHR-BPH-DIDE

  34. Background • Varicella outbreaks among school-aged children – high • 2007 ACIP two dose vaccination • To reduce the # and size of varicella outbreaks • To assess the impact of routine 2-dose varicella vaccination • To improve the knowledge about the changing epidemiology of varicella • To develop and refine appropriate public health interventions to control and prevent future varicella outbreaks WVDHHR-BPH-DIDE

  35. Background cont. • American Recovery and Reinvestment Act (ARRA) funding • West Virginia – one of 6 sites in the US • Two-year short-term project • 12/2009 to 12/2011 during school calendar • Hired 2 staff to assist school nurses: • Jeannie Shifflett: Varicella Surveillance Nurse • Stephen Frame: Varicella Project Coordinator WVDHHR-BPH-DIDE

  36. Objectives of the Project • To strengthen state and local health department capacity to detect and investigate varicella outbreaks among school-aged children in a systematic manner • To strengthen outbreak detection and response in order to evaluate vaccine impact and vaccine effectiveness • To determine varicella vaccine effectiveness in a school setting to evaluate effectiveness of two-dose varicella vaccination in the context of an outbreak WVDHHR-BPH-DIDE

  37. Activities for the Project • Varicella vaccine coverage estimates for WV public schools – SIIS and WV Education Information System (WVEIS) • Monthly varicella surveillance survey • Varicella outbreak investigation – DIDE with collaboration of public health nurse, regional epidemiologist to assist school nurses • Data analysis and reports – epidemiologists WVDHHR-BPH-DIDE

  38. Varicella Outbreak Investigation in Schools • Use varicella line list form/case report form • Demographic information • Clinical information • Onset date, severity • Vaccination information • Previous disease information • Laboratory testing WVDHHR-BPH-DIDE

  39. Moderate: 50-249 lesions, (can place hand on body without covering any lesions) Mild: < 50 lesions, (can easily count) Moderately severe: 250-499 lesions (hand placed on body will cover one or more lesions) Severe: 500+ lesions (difficult to see normal skin WVDHHR-BPH-DIDE

  40. Guidance for estimating number of lesions –proxy for disease severity • <50 Can count # easily within 30 seconds • 50 – <250 Patient’s hand can be placed on affected area without covering 1 or more lesions • 250 – <500 Patient’s hand cannot be placed on affected area without covering 1 or more lesions • ≥500 Cannot visualize normal skin WVDHHR-BPH-DIDE

  41. Varicella Vaccine Effectiveness Assessment Study • Case control study • Recruit well students from the same classroom/school • Collect data • Demographic information • Vaccination information • Previous disease information • Follow-up controls to verify if they develop disease 21 days after exposure. WVDHHR-BPH-DIDE

  42. School Nurse Resource Web Page • Outbreak Toolkit • Monthly Survey Link & Closure Dates • Protocol  • FAQ‘s • Additional Information • Emergency and other contact information www.wvidep.org Listed Under Hot Topics WVDHHR-BPH-DIDE

  43. Monthly Varicella Surveillance Survey for School Nurses How? • School nurse listserve used for contact • Email survey on 30th of every month • Survey deadline – 14th of the following month WVDHHR-BPH-DIDE

  44. Monthly Varicella Surveillance Survey for School Nurses Cont. What? • School demographic data • Any varicella case in the school for the month • Any varicella outbreaks in the school for the month • LHD contact information with outbreak cases WVDHHR-BPH-DIDE

  45. Sample of Monthly Varicella Survey WVDHHR-BPH-DIDE

  46. December Survey Data • 13 cases of Varicella reported during the month of December 2009 • No Varicella Outbreaks reported for December • A total of 343 public schools out of the 696 (49%) • A total of 151 school nurses have completed the survey. • Fourteen(14) Counties reported data for 100% of their total schools: Boone, Cabell, Clay, Gilmer, Hampshire, Hancock, Lewis, Mercer, Mingo, Ohio, Pleasants, Taylor, Tucker, and Wirt. WVDHHR-BPH-DIDE

  47. December Survey Data Cont. Percentages Reported by County Barbour: 11% Berkeley: 57% Brooke: 60% Fayette: 20% Grant: 20% Jackson: 50% Jefferson: 47% Kanawha: 12% Logan: 71% Marion: 21% Marshall: 77% Mason: 77% Mineral: 73% Monongalia: 71% Monroe: 50% Morgan: 75% Pocahontas:60% Preston: 17% Putnam: 82% Randolph: 67% Ritchie: 67% Roane: 50% Tyler:75% Upshur: 78% Wayne: 38% Webster: 17% Wetzel: 67% Wood: 85% Wyoming: 7% * note counties not shown reported 0% WVDHHR-BPH-DIDE

  48. January Survey Data • 19 cases of Varicella reported during the month of January 2010 • 1Varicella Outbreak reported for January • A total of 428 public schools out of the 696 (61%) • A total of 176 school nurses have completed the survey. • Fifteen(15) Counties reported data for 100% of their total schools: Boone, Brooke, Gilmer, Hampshire, Hancock, Lincoln, Logan, Mingo, Monroe, Pleasants, Taylor, Tucker, Tyler, Wayne, and Wirt. WVDHHR-BPH-DIDE

  49. January Survey Data Barbour: 0% Berkeley: 46% Boone: 100% Braxton : 25% Brooke : 100% Cabell: 65% Calhoun: 0% Clay: 0% Doddridge: 0% Fayette: 73% Gilmer: 100% Grant: 20% Greenbrier: 15% Hampshire: 100% Hancock : 100% Hardy: 0% Harrison: 4% Jackson : 42% Jefferson: 60% Kanawha : 71% Lewis : 0% Lincoln: 100% Logan: 100% Marion: 21% Marshall : 85% Mason: 80% McDowell: 0% Mercer : 71% Mineral : 82% Mingo : 100% Monongalia: 90% Monroe: 100% Morgan : 88% Nicholas : 0% Ohio: 69% Pendleton: 0% Pleasants: 100% Pocahontas :60% Preston : 8% Putnam : 86% Raleigh : 0% Randolph : 71% Ritchie : 67% Roane : 50% Summers: 0% Taylor : 100% Tucker : 100% Tyler : 100% Upshur: 89% Wayne : 100% Webster : 33% Wetzel : 67% Wirt : 100% Wood: 93% Wyoming : 69% WVDHHR-BPH-DIDE

  50. Increase In Response WVDHHR-BPH-DIDE

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