Definition Purpose: Created by the CDC National Syndromic Surveillance Program (NSSP) for use with
emergency department data to develop queries for all National Notifiable Diseases defined by the National
Notifiable Diseases Surveillance System (NNDSS). Please note that while the disease queries are
developed using the NNDSS case definition as the basis for identifying patient visits of interest, the queried
patient visits themselves may or may not represent a case patient in NNDSS and further public health
investigation will most often be required. This query is intended to be a version 1 and may be further
improved upon by the NSSP community of practice in the future. This query is intended to be narrow and
capture visits with specific terms to support greater monitoring and actionable public health data. More
complex and/or broader queries may exist that more broadly capture symptoms or travel-based terms.
New or Revised Definition: New Definition
Date Added to ESSENCE: October 2025
Definition Description: Designed to capture emergency department visits with a diagnostic code or textual
indicator of possible symptomatic rubella virus infections or congenital rubella syndrome. There are many
inappropriate IgM tests performed for rubella, particularly common as screening tests during pregnancy. A
recent study found that from 2019-2022, only 10.2% of IgM tests for rubella were appropriately performed
using HealthVerity administrative data.1
Inappropriate IgM tests can lead to false positive results and
unnecessary public health response and action. The volume of inappropriate IgM positives for rubella
outweighs true rubella incidence in the United States (since elimination in 2004, fewer than 10 cases have
been reported annually each year). Thus, this query was designed to be specific to individuals presenting
with congenital rubella syndrome, symptomatic rubella or known exposure to rubella, and not just diagnostic
codes indicative of test positivity.
See attached for full syndrome definition.