The federal map that millions of Americans check to see how much respiratory illness is circulating in their state has been rebuilt for the new season, and it is entering the fall with holes in three jurisdictions.
The CDC's Respiratory Virus Activity Levels page, updated Sept. 18, discloses that Iowa's data feed to the National Syndromic Surveillance Program was terminated on May 6 after the state changed health information exchange vendors. Only data through the week ending May 2 counted toward Iowa's new thresholds, and the page states that Iowa's activity levels display as unavailable for the weeks ending May 9 and later. Separately, the agency lists no emergency department data for South Dakota or Guam, and says Missouri's baseline had to be computed partly from neighboring states because of data quality problems.
For a family in Des Moines or Sioux Falls trying to decide whether to move a grandparent's birthday gathering indoors, that is not an abstraction. The state-level color on the national map is the fastest read most households have on whether illness is building where they live, and right now it is not the read those residents are getting.
Inside the Rebuilt Activity Scale
The activity levels are not a case count. The CDC uses an acute respiratory illness metric that sorts the share of emergency department visits for respiratory complaints into five categories, from very low to very high, so states can be compared on the same footing.
Those categories are not fixed. For each surveillance year, the agency identifies the historically quietest weeks in each of the 10 federal health regions, calculates a baseline from them, and rebuilds the thresholds. The page carrying the 2026-2027 version was first published in mid-August, which means the boundary between a moderate and a high week in any given state was recalculated this summer using the three previous surveillance years.
That reset is routine and defensible. It is also the reason missing months matter more than they might appear. A state whose recent history is incomplete has a thinner foundation under the label it will display all winter.
Missouri is the clearest illustration. The CDC states that Missouri's historical data before the week of March 2, 2025, could not be used, so data from Iowa, Kansas and Nebraska were substituted to compute Missouri's 2026-2027 levels, with Missouri's own data used from that point forward.
A separate gap affects forecasting rather than measurement. The CDC's epidemic trend estimates based on Rt for flu and RSV ended for the 2025-2026 season on May 29 and resume in fall 2026, so the model that indicates whether those infections are growing or declining is not yet running for the new season.
Behind the Iowa Outage
Iowa's interruption stems from a vendor transition rather than a funding decision. The Iowa Department of Health and Human Services states on its Promoting Interoperability Program page that "existing health information exchange services that facilitated syndromic surveillance in Iowa were terminated" on May 6, and that Iowa providers did not then operate in a jurisdiction able to receive electronic syndromic surveillance data in the required format. The department said it anticipated being ready to receive syndromic surveillance again no later than August.
Iowa's own respiratory reporting has continued through other channels. The state works with schools, local public health and the Iowa Department of Education on two systems, a 10 percent daily student absence threshold and weekly illness totals from sentinel schools. It also receives long-term care facility outbreak reports, runs a weekly laboratory testing survey and participates in the national outpatient influenza network. Those systems are separate from the federal emergency department feed that drives the national map.
South Dakota's absence is longer standing. The CDC's data notes list Guam and South Dakota among jurisdictions with no emergency department visit data available for this metric, a limitation the agency discloses rather than conceals.
The National Picture Underneath the Gaps
The top-line federal reading remains reassuring. As of Sept. 18, the CDC's Respiratory Illnesses Data Channel reports that the amount of acute respiratory illness causing people to seek health care is very low. COVID-19 activity is elevated and increasing nationally, though hospitalizations remain low overall. Rhinovirus and enterovirus, along with group A strep, are increasing nationally, a pattern the agency treats as expected once classrooms refill. RSV and seasonal flu activity are low.
Those two facts sit together uncomfortably. Nationally, this is a quiet moment. In three jurisdictions, the tool designed to tell residents when the quiet ends is partially offline.
Families in affected states are not without options. Iowa HHS publishes its own weekly respiratory virus surveillance report drawing on school, laboratory and long-term care data. State and county health department dashboards elsewhere often update on their own schedules and can be more current than the federal picture. The CDC's community snapshot still carries wastewater and laboratory positivity measures that do not depend on the emergency department feed, and its national COVID-19 wastewater data is reported at the state level.
The household decisions that matter in September do not hinge on a map color. Flu and COVID vaccines take roughly two weeks to reach full effect, and flu activity most often peaks between December and February. Timing questions for infants, older adults, pregnant people, and anyone with a chronic condition belong with a clinician rather than a dashboard.
MedicalDaily has previously reported on surveillance gaps widening over the summer as COVID positivity rose. What is new here is documentation, in the CDC's own methodology notes, of exactly which jurisdictions start the 2026-2027 season with incomplete inputs.
What remains unconfirmed is when Iowa's feed will be restored to the federal system and when its activity levels will reappear. Neither the CDC nor Iowa HHS has published a firm restoration date for the national display. The CDC updates the pages on Fridays, and flu and RSV trend estimates are due to resume this fall.
Key Questions Answered
What changed on the CDC page? The state activity level thresholds were rebuilt for the 2026-2027 surveillance year, and the agency disclosed data gaps affecting Iowa, Missouri, and South Dakota.
Why is Iowa's data missing? Iowa HHS says the health information exchange services supporting syndromic surveillance were terminated in early May during a vendor transition. Only data through the week ending May 2 was counted.
Does this mean illness is being missed in those states? Not necessarily. Iowa still tracks illness through school absenteeism, laboratory testing, outpatient networks, and long-term care reporting. The gap affects the federal emergency department display.
What does the national picture show right now? Overall respiratory illness is very low. COVID-19 is elevated and increasing, with low hospitalizations. Rhinovirus, enterovirus, and group A strep are increasing. Flu and RSV are low.
Where can affected residents check local activity? State health department respiratory reports, county dashboards, and CDC wastewater and laboratory positivity measures, which do not rely on the emergency department feed.
Should families change vaccination plans? No. Flu and COVID vaccines take about two weeks to take full effect, and flu most often peaks between December and February. Timing questions belong with a clinician.
When will flu and RSV trend estimates return? The CDC says those updates resume for the new season this fall.
