2014.ISDS.Abstracts.Final.pdf


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ISDS 2014 Conference Abstracts

Evaluating the Utility of HealthMap as a Supplementary 
Surveillance Tool

Melinda C. Thomas*, Aaron Kite-Powell, David Atrubin and Janet J. Hamilton

Florida Department of Health, Tallahassee, FL, USA

Objective
To assess the outbreak detection utility of HealthMap, a publically 

available event-based biosurveillance system utilizing various 
internet-based media resources to identify outbreaks, at the state and 
local level. Results may help determine whether HealthMap should be 
monitored more closely as a supplementary surveillance tool.

Introduction
HealthMap collects and aggregates information from online sources 

to generate outbreak alerts based on disease and geographic location. 
This project will assess the timeliness and sensitivity of HealthMap 
based on outbreak posts from EpiCom, the Florida Department of 
Health’s disease outbreak and health incident alert network.

Methods
This project compared EpiCom posts and HealthMap alerts in 

Florida for similarities in timing for outbreaks from January 1, 2009 
to August 31, 2013. The project assessed sensitivity and timeliness of 
HealthMap, whether both sources captured the outbreak, and which 
source’s post was earlier. HealthMap alert date was compared to 
EpiCom’s post date and the date the outbreak was reported to the 
county or state health department. Outbreaks of legionellosis, dengue, 
measles, and influenza and influenza-like illness (ILI) were assessed. 
Results for measles are described below. The variation of EpiCom 
post timeliness by county size was also investigated.

Results
During the study period, EpiCom reported on 13 confirmed measles 

outbreaks in Florida. Eight of these outbreaks were also found in 
HealthMap, giving HealthMap a sensitivity of 61.5% for measles. 
Two HealthMap measles posts based on non-U.S. media sources had 
no match to any EpiCom post. Based on post date, HealthMap was 
timelier than EpiCom for 2 of the outbreaks and just as timely for 
3 of the outbreaks. However, based on the date the county health 
department was notified in the EpiCom posts, regular state and local 
surveillance detection practices are timelier for 100% of the outbreaks.

Conclusions
Preliminary analysis suggests that HealthMap is useful for 

surveillance activity but not for initial outbreak detection by the 
state and local health department due to its relatively low sensitivity 
and timeliness of detection. However, due to its worldwide focus, 
it may be useful in providing a better international view of disease 
activity, which could be especially valuable for Florida for situational 
awareness and surveillance activity due to the large amount of 
international travelers who visit. Additionally, there was evidence 
suggesting public health is being too conservative in its utilization 
of EpiCom. HealthMap can also be a means of informing the general 
public of health concerns in their area and assisting public health in 
recognizing what events are in the news.

Keywords
Disease outbreak detection; Surveillance and alerting; Event-based 
biosurveillance; HealthMap

Acknowledgments

This project was supported in part by an appointment to the Applied 
Public Health Informatics Fellowship Program administered by CSTE 
and funded by a CDC Cooperative Agreement.

References

Freifeld CC, Mandl KD, Reis BY, Brownstein JS. HealthMap [Internet]. 
2014. Available from: http://www.healthmap.org.

*Melinda C. Thomas

E-mail: melinda.thomas2@flhealth.gov    

Online Journal of Public Health Informatics * ISSN 1947-2579 * http://ojphi.org * (1):e165, 201