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 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 2WVDHHR-BPH-DIDE

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 3WVDHHR-BPH-DIDE

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 4WVDHHR-BPH-DIDE

Epidemiology of Varicella cont. Incubation period: days (range days) Infectious period: 1-2 days before the rash to crusting of all lesions Secondary infection (household contacts): % 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 5WVDHHR-BPH-DIDE

Disease Burden Prevaccine Era in U. S. ~ 4 million cases of varicella 10,500-13,000 hospitalizations (range 8, ,000) 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 6WVDHHR-BPH-DIDE

Specimen collection video vac/varicella/ 7WVDHHR-BPH-DIDE

Diagnostic Tests for Varicella-Zoster Virus (VZV) Infection TestSpecimenComments PCRVesicular swabs or scrapings, scabs from crusted lesions, biopsy tissue, CSF Very sensitive method. Specific for VZV, RT (not readily available) distinguish vaccine strain from wild-type, requires special equipment DFAVesicle scraping, swab of lesion base (must include cells) Specific for VZV, more rapid and more specific than culture, less sensitive than PCR 8WVDHHR-BPH-DIDE

Varicella Vaccination in the U. S. One –doseTwo-dose Licensure1995 ACIP Recommendation Age12-15 months of age 13 years and older without evidence of immunity should receive 2 doses, 4-8 weeks apart. First dose – months Second dose – 4-6 years of age 13 years and older without evidence of immunity should receive 2 doses, 4-8 weeks apart. Vaccine coverage90% (One dose among children months of age in U. S.) Vaccine Efficacy97% (12 months-12 yrs.)99% (13 years and older) Effectiveness: 70-90% against any varicella disease % against severe varicella disease 9WVDHHR-BPH-DIDE

Varicella Surveillance in West Virginia

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 11WVDHHR-BPH-DIDE

Varicella Case Definition (2010) 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. 12WVDHHR-BPH-DIDE

Varicella Case Definition 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. 13WVDHHR-BPH-DIDE

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

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 18WVDHHR-BPH-DIDE

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

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) 20WVDHHR-BPH-DIDE

School “A” Varicella Outbreak Case Case Case Case Case Do any of these cases make up an outbreak? 2.If so, which of the cases make the outbreak? 21WVDHHR-BPH-DIDE

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 22WVDHHR-BPH-DIDE

Line listing form 23WVDHHR-BPH-DIDE

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 24WVDHHR-BPH-DIDE

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

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: WVDHHR-BPH-DIDE

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 27WVDHHR-BPH-DIDE

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Day Care # school (# cases) Elementary # schools (# cases) Middle # school (# cases) High # school (# cases) Total # school (# cases) 20071(34)6(99)1(7)08(140) (51)4(29)1(22)9(102) (8)1(10)02(18) Median #:11(range: 5-40) Varicella Outbreaks N=19 29WVDHHR-BPH-DIDE

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

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

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 34WVDHHR-BPH-DIDE

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 35WVDHHR-BPH-DIDE

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 36WVDHHR-BPH-DIDE

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 37WVDHHR-BPH-DIDE

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 38WVDHHR-BPH-DIDE

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

<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 Guidance for estimating number of lesions – proxy for disease severity 40WVDHHR-BPH-DIDE

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. 41WVDHHR-BPH-DIDE

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

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

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 44WVDHHR-BPH-DIDE

Sample of Monthly Varicella Survey 45WVDHHR-BPH-DIDE

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. December Survey Data 46WVDHHR-BPH-DIDE

December Survey Data Cont. 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% Percentages Reported by County 47WVDHHR-BPH-DIDE

January Survey Data 19 cases of Varicella reported during the month of January Varicella 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. 48WVDHHR-BPH-DIDE

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% 49WVDHHR-BPH-DIDE

Increase In Response 50WVDHHR-BPH-DIDE

QUESTIONS ? THANK YOU