CDC reports U.S. influenza test positivity at 3.4% in week 38
In the week ending 26 September, clinical laboratories tested 33,547 respiratory specimens and 1,151 were influenza-positive. CDC said national influenza activity remained low but was increasing.
Event / data period: 2026-09-26
Published: · Updated:
In its week-38 FluView report published on 2 October, the U.S. Centers for Disease Control and Prevention (CDC) reported that 1,151 of 33,547 respiratory specimens tested by clinical laboratories were positive for influenza, a positivity rate of 3.4%. Of the positive specimens, 1,108 were influenza A (96.3%) and 43 were influenza B (3.7%). CDC characterized national seasonal influenza activity as low but increasing.
During the same week, 1.7% of visits reported to the outpatient network tracking influenza-like illness involved fever with cough or sore throat. That syndromic indicator is not a count of laboratory-confirmed influenza; the symptoms can also be caused by other respiratory viruses. The laboratory table counts tested specimens, not patients, and more than one specimen may come from a person.
Data
CDC U.S. influenza laboratory surveillance, 2026 epidemiologic week 38
National respiratory-specimen testing by clinical laboratories for the week ending 26 September, in CDC’s weekly report dated 2 October 2026.
- Share of respiratory specimens positive for influenza in clinical laboratories; 33,547 tested, week ending 26 September 2026
- 3.4 percent
- 2026-09-26 · Observed
- Respiratory specimens tested by clinical laboratories, weekly total
- 33,547 count
- 2026-09-26 · Observed
- Influenza-positive specimens in clinical laboratories, weekly total
- 1,151 count
- 2026-09-26 · Observed
- Influenza A share among influenza-positive clinical-laboratory specimens
- 96.3 percent
- 2026-09-26 · Observed
Methodology
The 3.4% is 1,151 influenza-positive specimens among 33,547 respiratory specimens tested by clinical laboratories; it is not a count of cases or people. The A/B shares describe the distribution among positive specimens. CDC uses clinical-laboratory results to monitor whether activity is rising or falling; the report says national activity was low but increasing.
Updated:
Subjects and places
Subject proposals
- Communicable diseaseSuggested
- Subject suggested from the title or summary: influenzawww.cdc.gov ↗
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- United States · Place role: Coverage · Place type: Country or area · Location precision: RegionalEvidence
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