The new flu season has begun in the United States, with millions of Americans expected to contract the virus. While most cases resolve within a few days, a minority of patients experience lingering symptoms that can persist for months, a condition now referred to as “long flu.” The prolonged illness mirrors long Covid, affecting respiratory function and sometimes causing inflammation that impacts organs such as the brain, leading to memory problems and sleepiness.
A study by researchers at WashU Medicine examined the medical records of over 10,000 flu‑hospitalized patients and 80,000 Covid‑hospitalized patients. Findings showed that complications were still reported up to 18 months after infection. Long flu was linked to chest pain, rapid heart rate, cough, shortness of breath, low blood oxygen, and an increased risk of Type 1 diabetes. Dr. Ziyad Al‑Aly estimated that 3‑5 % of those who contract the flu may develop long‑term symptoms, though the exact figure remains uncertain.
Vaccination remains the most effective defense against both short‑term and long‑term flu complications. Flu shots have been associated with reduced risks of Alzheimer’s disease and severe cardiovascular events, and newer mRNA flu vaccines offer even greater protection. Despite these benefits, vaccination rates have fallen in recent years, prompting experts to emphasize the importance of timely immunisation.
Health professionals advise receiving the flu shot between Halloween and Thanksgiving to ensure protection lasts through the peak of the season, which can extend into April or May. Early data show a rise in emergency department visits for flu in the West, an atypical pattern that usually begins in the Southeast. According to the CDC, flu causes between 9.4 and 51 million illnesses annually and results in 6,300 to 52,000 deaths.
