Not by itself - only viruses cause colds - but cold air measurably weakens the nose's local defenses: a 2022 study found chilled nasal lining releases fewer antiviral extracellular vesicles, each carrying less cargo and binding virus less tightly.
Earlier research showed the innate antiviral response runs worse at cooler airway temperatures. So: cold does not create infection, but a chilled nose is a worse-defended nose, and winter's indoor crowding does the rest. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper .
What to do
Common questions
Does being cold make you sick?
Not by itself - only viruses cause colds - but the grandmotherly warning has earned a partial vindication: cold air measurably weakens the nose's local immune defenses. A 2022 study in the Journal of Allergy and Clinical Immunology mapped the mechanism: the nasal lining fights invading viruses partly by releasing swarms of extracellular vesicles that neutralize and flag them, and cold exposure - the kind that drops the temperature inside the nose a few degrees - impaired that defense: fewer vesicles released, and each one packed less antiviral cargo and bound virus less tightly. Earlier mouse-airway research had already shown the innate antiviral response works worse at cooler temperatures. So the accurate sentence: being cold does not create infection, but a chilled nose is a worse-defended nose, and in virus season that defense gap - plus winter's indoor crowding and dry air - is how "I got chilled and caught something" becomes true. Covering up is comfort; the real winter moves are ventilation, hand hygiene, and keeping distance from the visibly sick.