Silence in a terminal can hide risk. Health officials now say travelers who passed through Logan Airport Terminal C during a narrow overnight window may have been exposed to measles, after a man later confirmed with the virus arrived on an incoming flight and moved through the concourse and adjacent areas.

This warning is not alarmist theater; it is basic virology. Measles spreads through respiratory droplets and fine aerosol, and the virus can remain infectious in the air and on surfaces for hours, a property tied to its high basic reproduction number and intense viral shedding in the upper respiratory epithelium. Anyone in the terminal zone around that time, even without direct contact, is considered potentially exposed under standard epidemiologic definitions.

The real concern lies with immunity gaps. While two documented doses of the measles, mumps, and rubella vaccine provide strong humoral and cellular protection, pockets of under-vaccinated adults and children persist, and they are the ones most likely to develop fever, cough, conjunctivitis, and the characteristic rash that can precede complications such as pneumonia or encephalitis. Public health agencies are urging those who were in Terminal C during the specified period to review their vaccination records, monitor for symptoms, and seek serologic testing or post-exposure prophylaxis if advised by clinicians.