Registries are booster for health
Registries are booster for health
Data warehouses help states, counties ensure immunization
Arizona's Kathy Fredrickson helps create GISes that can track levels of childhood immunization.
By Trudy Walsh
To help track childhood vaccinations, many state and county health departments are setting up automated immunization registries.
According to the U.S. Centers for Disease Control and Prevention, 11 states have laws that mandate immunization reporting, while almost half the states have laws that authorize immunization registries.
CDC officials recommend that by age 2, children should have received a series of 14 or 15 doses of vaccines for diphtheria, tetanus, pertussis, polio, measles, mumps and other diseases.
The worry is that many children will miss these vaccinations or receive the same vaccine twice because there is no comprehensive national tracking system or all-encompassing legislation that requires immunization registration. An underimmunized population is at the greatest risk for epidemics.
Add the increased mobility of families and the ever-changing face of health insurance coverage, and the situation becomes even more dangerous.
Some health departments are taking a cue from geographic information systems and using one of epidemiology's oldest and handiest tools. History shows that the mapping of disease data has proved effective when other methods failed.
In 1854, Dr. John Snow plotted the location of deaths from cholera in a London neighborhood. Snow marked deaths by dots and showed the location of the neighborhood's water pumps with crosses (see box, Page 33). Snow's map showed that the highest concentration of deaths occurred near the Broad Street water pump. The water pump handle was removed, and the epidemic ended.Modern times
Arizona's Health Services Department gets good results from an updated version of Snow's methods by using 133-MHz Pentium PCs and ArcView GIS mapping packages from Environmental Systems Research Institute of Redlands, Calif. In 1998, when the Arizona State Immunization Information System (ASIIS) began operating, childhood immunization in the state rose from 71 percent to 78 percent.
Arizona officials recently began incorporating a GIS mapping feature into their immunization tracking system. ASIIS will be able to plot digitally those areas where children are underimmunized, said Kathy Fredrickson, program manager for ASIIS.
ASIIS officials are working with Scientific Technologies Corp. (STC) of Tucson, Ariz., to develop the GIS, which runs ArcView versions 3.1 and 3.2.
ASIIS can create a digital immunization data map in a few steps, said Brad Tatham, GIS analyst for STC. STC created GIS middleware called QuickMap that retrieves patient data from Arizona's central immunization registry, which is stored in an Oracle7 database on a Sun Microsystems Inc. server in Phoenix, Tatham said.Right there
The ASIIS GIS will show where specific disease outbreaks occurred, and at a glance will show the relationship between disease outbreaks and immunization levels.
'We can then make sure there are health services or other types of intervention provided in those areas,' Fredrickson said. 'You'll be able to drill down to different levels of information. You'll be able to say, show me immunization data on just 2-year-olds, or just 5-year-olds.'
One of the challenges states face is creating smooth interfaces with other systems. Most state immunization registries have some connection with birth certificate data, which in most cases runs on a different system.
Florida's immunization registry automatically uploads information about newborns from the Vital Statistics Department's birth records, accounting for nearly 190,000 new records each year, said Susan Lincicome, a senior management analyst with the Florida Health Department's Bureau of Immunization.
This year, five Florida counties linked their immunization data to the registry. By next year, all 67 county health departments will be linked to the registry, which is stored on a relational database written in M, a medical information systems language formerly known as Mumps, Lincicome said. The database runs Cache Version 2.1.7, which is Microsoft Windows NT-compatible application development software from Intersystems Corp. of Cambridge, Mass.
Since 1995, when Florida health departments began using the registry software, there has been a notable increase in immunization rates, Lincicome said. The percentage of 2-year-olds with complete immunization coverage has increased substantially, from 80 percent in 1995 to 86.2 percent in 1998, Lincicome said. The software also helps health department officials remind parents about needed immunizations, she said.
The registry backbone is TCP/IP on a 400-MHz switch, Lincicome said. Two 500-MHz Dell PowerEdge 6300 servers with 256M of RAM each run NT 4.0 Server on a closed domain system. The registry network has a dedicated 100M hub with smart switching, she said.
Mapping epidemiological data has proved effective since 1854, when Dr. John Snow plotted the location of 500 deaths from cholera in a London neighborhood, left. Deaths are represented by dots, and the pumps where residents got their water are represented by crosses. Based on this map, Snow observed that almost all the cholera deaths occurred among residents who drank from the Broad Street water pump.
''Today's sophisticated GIS packages, such as the Arizona Health Department's, top, follow the same principles as Snow's map, but Arizona officials can plot in seconds what took months for Snow. In the Arizona map, analysts show a correlation between the red dots, which represent underimmunized populations, and the outbreak of flu, hepatitis A, measles and other illnesses, displayed as brightly colored triangles.
The primary and backup domain controllers for the registry are two Dell PowerEdge Quad 6100 200-MHz servers with 1G of RAM, RAID Level 5 storage and 45G hard drives. The department plans to beta-test the registry on the Web in the spring, with a 200-MHz Dell PowerEdge Quad 6100 Web server with 512M of RAM and a 9G hard drive, Lincicome said. Security is provided by a dual 266-MHz Dell PowerEdge 4200 firewall server with 128M of RAM and a 9G hard drive.
Both Florida and Michigan registries give parents the choice of opting out of the registry so the child's immunization records will not be entered or shared.
Michigan, like Arizona, is one of the 11 states with mandated immunization reporting requirements. Michigan's immunization registry contains a full terabyte of immunization data, said Gillian Stoltman, director of Michigan's Immunization Division. Vaccination records on 1.6 million children are stored in the registry's data warehouse, which resides on a DPS 9000 mainframe from Bull HN Information Systems Inc. of Billerica, Mass.
Minnesota Health Department officials have linked their immunization registry to maternity records. Birth data is transmitted from the hospital into the state's immunization registry in real time, said John Oswald, director of the Minnesota Health Department's Center for Health Statistics. 'Time is of the essence because the first routine immunizations come at age 2 months,' he said.
Minnesota health officials worked with ManTech International Corp. of Fairfax, Va., to integrate a client-server vital statistics system, dubbed the VRV2000, with the immunization system. The system runs under Windows 95, NT or 98 with an Oracle7 database.
The Minnesota system has built in a level of sensitivity to families, Oswald said. Officials can download into the system not only birth certificate data, but death certificates as well.
'You want to make sure you don't send a six-month immunization reminder to the parent of an infant who dies at 5 months,' Oswald said. The system will flag that infant death, and make sure the record is removed from the immunization reminder system. 'It's a rare case of using technology to be more sensitive to families,' he said.
The ManTech system will be accessible from Pentium PCs in 100 county offices, 100 hospitals and 500 funeral homes by 2001.