ISDS Annual Conference Proceedings 2019. This is an Open Access article distributed under the terms of the Creative Commons AttributionNoncommercial 4.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 11(1): e286, 2019 ISDS 2019 Conference Abstracts Improving Varicella Investigation Completeness in Pennsylvania Jonah Long, Wayne Fleming, Janine Strick Pennsylvania Department of Health, Jackson Center, Pennsylvania, United States Objective The objective of this study was to evaluate the impact of efforts made to improve the completeness of select varicella (chickenpox) case investigation variables. Introduction Routine childhood administration of varicella-containing vaccine has resulted in the number of varicella (chickenpox) cases in Pennsylvania falling from nearly 3,000 cases in 2007 to less than 400 cases in 2017. Prior to 2018, the completeness of varicella case investigation data documented in Pennsylvania’s electronic disease surveillance system (PA-NEDSS) was not routinely monitored by Department of Health (DOH) staff. A pilot project was initiated in April 2018 to monitor and improve completeness of select varicella case investigation variables. Methods Varicella cases reported to PA-NEDSS during MMWR year 2018 (MMWR weeks 1 – 26) in Pennsylvania (excluding Philadelphia County) with a classification status of probable or confirmed were included in the pilot project (n=223). DOH epidemiology staff prioritized 11 key varicella investigation variables and developed a SAS program to identify cases with missing data, which w ere summarized in weekly reports and provided to DOH immunization staff for follow- up. DOH immunization staff reviewed missing data reports and communicated with case investigators to reconcile missing data. Varicella case data from the project period were compared with a 10-year baseline to evaluate the 11 targeted variables for change in percent completion. Results Percent completion of all 11 variables improved during the intervention period, with a median relative increase of 10.2% (ran ge: 4.2% — 25.5%) compared to baseline. All but two variables (pregnancy status and number of days hospitalized) exhibited a statistically significant (p<0.05) improvement in percent completion. In addition, among eight variables that include an unkn own response option, only one variable (number of varicella vaccine doses received) measured an increase in the percentage of unknown responses during the project period compared with baseline; however, this increase was not statistically significant (p=0.180 ). Conclusions Prioritization of key varicella investigation variables for improved completion was successful and did not result in significant increases of unknown responses. As varicella cases become less common, varicella case investigation data become increasingly important. Increased completeness of these data will enhance DOH communication of varicella surveillance findings, particularly for severe cases. Based on the success of this interagency collaboration, similar efforts are being developed for additional reportable conditions. Table 1. Varicella variable completeness during 2008-2017 and 2018. Variable 2008-2017 (n=8,895) 2018 (n=223) http://ojphi.org/ ISDS Annual Conference Proceedings 2019. This is an Open Access article distributed under the terms of the Creative Commons AttributionNoncommercial 4.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 11(1): e286, 2019 ISDS 2019 Conference Abstracts Mean Percent Complete (standard deviation) Percent Complete Relative Percent Change χ2 p- valu e Onset date 92.4 (2.9) 99.6 +7.8 <0.001 Hospitalization 90.8 (5.0) 100.0 +10.2 <0.001 Days hospitalized1 72.4 (11.7) 90.9 +25.5 0.1614 Pregnant2 89.8 (3.2) 97.7 +8.8 0.05904 Rash onset date 94.2 (1.3) 99.6 +5.7 <0.001 Lesion severity 89.9 (1.7) 99.6 +10.7 <0.001 Immunocompromised 81.5 (4.9) 99.6 +22.1 <0.001 Complications 81.2 (7.4) 99.6 +22.6 <0.001 Transmission setting known 82.9 (4.5) 99.6 +20.1 <0.001 Received varicella vaccine 90.9 (1.8) 99.6 +9.5 <0.001 Varicella vaccine doses received3 96.0 (1.7) 100.0 +4.2 0.02044 1Denominator: Hospitalized cases; n=167 (2008-2017), n=11 (2018); 2Denominator: Female cases, >12 years; n=1,001 (2008- 2017), n=44 (2018); 3Denominator: Vaccinated cases; n=5,037 (2008-2017), n=79 (2018); 4Fisher exact (right-sided) http://ojphi.org/