Respiratory Illness Rates Continue to Rise as 2026 Begins

Respiratory illness activity continues to increase across the United States as we enter the new year. CIDRAP has the news.

Pertussis cases are rising, and a spike in Arkansas is driving case numbers up across the nation. There were over 500 cases reported in 2025, which marks the “highest annual total since the state began collecting data on pertussis 15 years ago.” Children and adolescents make up the majority of the cases in the state, with infants younger than 1 year old accounting for over 60% of hospitalizations.

Seasonal influenza activity also “remains elevated and is increasing across the United States.” Influenza A(H3N2) viruses continue to predominate, and a large portion of circulating strains (nearly 90%) belong to subclade K. The emergence of the subclade has “fueled an earlier-than-usual start to the flu season and given rise to higher case counts across parts of the country and globe.” The CDC estimates “at least 7.5 million illnesses, 81,000 hospitalizations, and 3,100 deaths from the flu so far this season.”

COVID-19 infections are also “growing or likely growing in 39 states, with no states showing clear declines in transmission.”