Influenza Season Winds Down in South Dakota: A Look at 2025-2026 Data

Northeast Radio SD News – South Dakota - Public health officials report that the 2025-2026 influenza season in South Dakota is beginning to wind down after peaking in early February. However, newly released data from the Department of Health (DOH) reveal that this season has been more active than the historical average, driven largely by an aggressive strain of the virus.

As of March 25, 2026, the state has recorded 16,670 confirmed cases and 905 hospitalizations. While these numbers are lower than the record-breaking 2024-2025 season, they remain well above the state’s eight-year average.

The 2025-2026 Season at a Glance

The current season has been dominated by the Influenza A (H3N2) strain. Health experts often associate H3N2 years with more severe illness, particularly among the elderly and young children.

Metric	2025-2026 Season (Current)	2017-2025 Average
Dominant Virus	A (H3N2)	Mixed (A/B)
Confirmed Cases	16,670	12,504
Hospitalizations	905	690
Deaths	25	40
Peak Week	February 2nd Week	February 1st Week

National Context and the “Subclade K” Variant

Nationally, the CDC has classified this season as “moderately severe.” Surveillance indicates that a specific variant of the virus, known as H3N2 subclade K, emerged after the current year’s vaccine was finalized. This “antigenic drift” has led to slightly lower vaccine effectiveness in some regions, contributing to the higher-than-average hospitalization rates seen in South Dakota.

Despite this, state epidemiologists stress that the vaccine remains the best defense against severe outcomes. Even with a partial match, those who are vaccinated are significantly less likely to require intensive care or experience fatal complications.

Impact on Northeast South Dakota

While the first fatalities of the season were reported in Minnehaha County earlier this winter, rural communities in Northeast South Dakota have felt the strain on local clinics. With activity now trending downward from the February peak, health officials are urging residents not to let their guard down.

“Influenza can be a very serious illness,” said Dr. Joshua Clayton, State Epidemiologist. “Taking preventative measures like regularly washing hands, covering your cough, and staying home when sick protects not just yourself, but your neighbors.”

Resources and Reporting

For those seeking more detailed data or looking to report respiratory outbreaks, the Department of Health provides several online resources:

·         Influenza Dashboard: doh.sd.gov/health-data-reports

·         Report a Case: sd.gov/diseasereport

·         CDC FluView: cdc.gov/fluview