Issue 11 - May 2003 : SYNDROMIC SURVEILLANCE IS ALIVE AND WELL IN NEW YORK CITY

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SYNDROMIC SURVEILLANCE IS ALIVE AND WELL IN NEW YORK CITY

While syndromic surveillance is just getting started or being budgeted in many cities across the country, New York City’s Health Department has performed a form of syndromic surveillance since the late 1990’s. Their investment in computerized surveillance increased after the events of September 2001. The current system tracks more than 50,000 pieces of information daily, including 911 calls, emergency room visits, and drug store purchases. (1)

Where did the idea for syndromic surveillance begin? In 1993, Milwaukee’s water supply became contaminated with Cryptosporidium. As a result, thousands of people developed diarrhea and over 100 people died. It took weeks to recognize the problem. Looking back, syndromic surveillance would have identified the outbreak at the outset, preventing much of the resulting morbidity and mortality.

Recognizing the need for a better way to identify problems quickly, Dr. Farzad Mostashari, assistant commissioner for epidemiology services for the New York City Department of Health, began gathering data from the city’s 911 system. Each day, a computer file with medical calls for the previous 24 hours was sent to the health department. The file included each patient’s age, sex, zip and chief complaint.

Of course, September 11, 2001 changed everything. Immediately after this catastrophe, the NYC Health Department began monitoring major emergency rooms, for unusual “syndromes”. At first, they placed their own staff in emergency rooms to take notes on every patient. Later, they had emergency personnel fax them daily reports, which were typed into a computer system at the health department. Both systems were cumbersome and costly.

Eventually, an electronic data interchange system was developed which allowed hospitals to send a daily computer file. Currently, three-quarters of the city’s total Emergency Visits are included in this daily report. The health department computer system then sorts the data by zip codes and by “matching medical terms with their synonyms”. It even adjusts for the numbers of emergency room visits during the week versus the weekend.

Dr Mostashari feels that this system, in its present form, is most effective for detecting naturally occurring outbreaks, rather than insidious bioterrorist attacks. But it’s “very much a work in progress.” Recently, the system detected the onset of flu season much earlier than their traditional methods did. Last fall, it identified an outbreak of Norwalk-like virus in time to give doctors early awareness of the outbreak so they could remind patients of the personal safety precautions that would prevent its spread.

In summary, the bad news is the threat of bioterrorism is a fact of life and every health department has a responsibility to monitor and prepare for it. The good news is that as a result of pioneering efforts in New York City and elsewhere, cities desiring to begin syndromic surveillance don’t have to start with human observers or faxed daily logs of emergency room visits. Syndromic surveillance software exists that computerizes the task, allowing the Health Department to spend time analyzing the data rather than spending time collecting or entering it. Now is a good time to be examining these systems and determining which will work best for your locale.

(1) Perez-Pena, Richard: System in New York for Early Warning of Disease Patterns. The New York Times. April 24,

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