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ISDS 2012 Conference Abstracts

An Integrated Syndromic Surveillance System for
Monitoring Scarlet Fever in Taiwan
Wan-Jen Wu*, Yu-Lun Liu, Hung-Wei Kuo, Wan-Ting Huang, Shiang-Lin Yang and Jen-
Hsiang Chuang

Epidemic Intelligence Center, Taiwan Centers for Disease Control, Taipei City, Taiwan

Objective
To develop an integrated syndromic surveillance system for timely

monitoring and early detection of unusual situations of scarlet fever
in Taiwan, since Hong Kong, being so close geographically to Tai-
wan, had an outbreak of scarlet fever in June 2011.

Introduction
Scarlet fever is a bacterial infection caused by group A strepto-

coccus (GAS). The clinical symptoms are usually mild. Before Oc-
tober, 2007, case-based surveillance of scarlet fever was conducted
through notifiable infectious diseases in Taiwan, but was removed
later from the list of notifiable disease because of improved medical
care capacities. In 2011, Hong Kong had encountered an outbreak of
scarlet fever (1,2). In response, Taiwan developed an integrated syn-
dromic surveillance system using multiple data sources since July
2011.

Methods
More than 99% of the Taiwan population is covered by National

Health Insurance. We first retrospectively evaluated claims data from
the Bureau of National Health Insurance (BNHI) by comparing with
notifiable diseases reporting data from Taiwan Centers for Disease
Control (TCDC). The claims data included information on scarlet
fever diagnosis (ICD-9-CM code 034.1), date of visits, location of
hospitals and age of patients from outpatient (OPD), emergency room
(ER) and hospital admissions. Daily aggregate data of scarlet fever
visits or hospitalizations were prospectively collected from BNHI
since July 2011. Over 70% of the deaths in Taiwan are reported to
the Office of Statistics of Department of Health electronically. We
obtained daily data on electronic death certification data and used
SAS Enterprise Guide 4.3 (SAS Institute Inc., Cary, NC, USA) for
data management and analysis. Deaths associated with scarlet fever
or other GAS infections were identified by text mining from causes
of death with keywords of traditional Chinese ‘scarlet fever’, ‘group
A streptococcus’ or ‘toxic shock syndrome’ (3).

Results
From January 2006 to September 2007, the monthly OPD data

with ICD-9-CM code 034.1 from BNHI showed strong correlation
with TCDC’s notifiable disease data (r=0.89, p<0.0001). From July
6, 2008 (week 28) through July 28, 2012 (week 30), the average
weekly numbers of scarlet fever visits to the OPD, ER and hospital
admissions were 37 (range 11–70), 7 (range 0–20) and 3 (range 0–9).
Eighty-five percent of the scarlet fever patients were less than 10
years old. In Taiwan, scarlet fever occurred year-round with seasonal
peaks between May and July (Fig. 1). From January 2008 to July
2012, we identified 12 potential patients (9 males, age range 0–82
years) who died of GAS infections. No report had listed ‘scarlet fever’
as cause of death during the study period.

Conclusions
Taiwan has established an integrated syndromic surveillance sys-

tem to timely monitor scarlet fever and GAS infection associated
mortalities since July 2011. Syndromic surveillance of scarlet fever
through BNHI correlated with number of scarlet fever cases through
notifiable disease reporting system. Text mining from cause of death
with the used keywords may have low sensitivities to identify pa-
tients who died of GAS infection. In Taiwan, syndromic surveillance
has also been applied to other diseases such as enterovirus, influenza-
like illness, and acute diarrhea. Interagency collaborations add values
to existing health data in the government and have strengthened
TCDC’s capacity of disease surveillance.

Fig. 1. Weekly numbers of nationwide scarlet fever OPD and ER visits, and
hospital admissions, with baseline OPD visits and 95% confidence interval
calculated by a Serfling’s model, week 28 of 2008 to week 30 of 2012.

Keywords
syndromic surveillance; Taiwan; scarlet fever; claims data

Acknowledgments

We thank the Bureau of National Health Insurance and Office of Statis-
tics of Department of Health for providing data required for this study.

References

1.Hsieh YC, Huang YC. Scarlet fever outbreak in Hong Kong, 2011. J
Microbiol Immunol Infect. 2011;44:409-11.

2.Tse H, Bao JY, Davies MR, et al. Molecular characterization of the 2011
Hong Kong scarlet Fever outbreak. J Infect Dis. 2012;206:341-51.

3.Chen PJ, Wu WJ, Huang WT, Chuang JH. An early warning system for
pneumonia and influenza mortality in Taiwan. Emerging Health
Threats Journal 2011;4: 11024.

*Wan-Jen Wu
E-mail: teatea@cdc.gov.tw

Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * 5(1):e160, 2013