Infection Control

ESSENCE provides hospitals with early flu virus detection

Briefings on Infection Control, December 1, 2009

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When H1N1 outbreaks were first encountered in April, the Maryland Department of Health was one of the first to notice a trend in flulike illnesses.

The state had been on a mission to achieve 100% hospital compliance by June 30, 2009, within the state-run Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE). In December 2008, 17 hospitals were on board, and by June 1, 2009, all 46 had joined, making Maryland the first state with 100% compliance.

So when alerts began showing up in the spring for outbreaks of flulike illnesses, some employees at the state department thought the system was broken, says Fran Phillips, deputy secretary for public health at the Maryland Department of Health and Mental Hygiene in Baltimore.

“For a while, we honestly thought we had some kind of data interference or it was some sort of programming error, but then we linked that to some of the other data sources we had and we realized we were seeing people who were at the leading edge of what later came to be positive lab tests of H1N1,” Phillips says.

By June, ESSENCE tracked the virus in all 46 hospitals throughout the state and has continued to track the H1N1 virus as flu season hit this fall.

“We’re watching now for the first time how this virus is going to behave in a large population in a flu season,” Phillips says. “That’s why everyone is looking at how the emergency room volume rates relate to the severity of the individuals admitted to the hospital, either in regular medical beds or ICU beds. It’s a really important way to determine how moderate or severe this illness will be.”

How it works
ESSENCE delivers a simple and very broad set of data to the state department of health because it only sorts cases based on the patient’s chief complaint. Data from each hospital are collected every day and batched at midnight, which staff members at the health department receive each morning. Two dedicated epidemiologists comb through the data and look for correlations or irregularities.

There are also algorithms built into the system that initiate alerts if a particular hospital is seeing an increased complaint above the expected level. Yellow or red alerts are issued depending on the number of complaints.

“That might warrant a call right then to the hospital to get some more clarifying information about individual pieces or do some investigation if right away it’s something we need to track,” Phillips says.
These calls often lead to more specific information that the hospital has on file, but isn’t included in the database for privacy reasons.

“If there is a phenomenon we are concerned about, we’ll call the hospital but we will have an identifier that they can trace to the medical records and so they can see where it came from,” Phillips says. “For example, if we saw four cases of severe food outbreaks, we wouldn’t necessarily know if those were people in the same family or people who had eaten in the same restaurant, but they would know that.”
The health department also tracks the data on a daily basis against some of the other laboratory databases and issues weekly reports to the governor, all 46 hospitals, and some larger clinics to provide situational awareness.

The data collected are not very specific, but they provide a very early indication of particular trends around the state. This allows the state to alert hospitals in a certain area to expect a surge of patients or communicate with the public about how to protect themselves before receiving confirmed lab results.

This is an excerpt from a member only article. To read the article in its entirety, please login or subscribe to Briefings on Infection Control.

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