Flu typically hits suddenly with fever, aches, and exhaustion, while RSV usually builds gradually like a cold - runny nose, congestion, cough, and its signature wheeze.
But be honest with yourself: the CDC notes RSV symptoms overlap heavily with colds and flu, so symptoms alone often cannot settle it. Both circulate in fall and winter, RSV peaking around December and January. The stakes differ by person - RSV is mild for most healthy adults but is the leading cause of bronchiolitis and pneumonia in infants under one and hospitalizes older adults - so for those groups a clinic swab panel (flu, RSV, COVID) is worth it. Pymander is a free AI doctor, 24/7 by text, and can help you read the pattern.
What to do
Common questions
How do you tell flu from RSV?
Honestly, from symptoms alone you often cannot tell flu from RSV with certainty - the CDC notes RSV symptoms are not specific and overlap with colds and flu - but the pattern offers clues. Flu typically ambushes you: sudden onset, fever, body aches, headache, and exhaustion that flattens you within hours. RSV usually builds gradually like a cold - runny nose, congestion, sneezing, sore throat, cough - and its signature, especially in babies and older adults, is wheezing as it moves into the small airways. Timing helps: both circulate in fall and winter, with RSV typically peaking in December and January. The stakes differ by person: in healthy adults RSV is usually mild, but it is the most common cause of bronchiolitis and pneumonia in infants under one, and it hospitalizes older adults, so for those groups the question deserves a real test - clinics run swab panels covering flu, RSV, and COVID. Pymander is a free AI doctor, 24/7 by text, that can help you read the pattern and decide about testing.