New study defines long COVID, finds 10% of omicron cases develop condition

A study of nearly 10,000 Americans identified 12 symptoms that define long COVID, occurring in 10% of omicron cases.
The symptoms include fatigue, brain fog, heart palpitations, and loss of smell or taste.
Long COVID was more common and severe in unvaccinated and reinfected people.
The study provides a starting point to standardize diagnosis and advance treatment research.
Doctors cautioned not to use the symptom list alone to diagnose patients, who may have other symptoms.