U.S. Centers for Disease Control and Prevention (CDC) on Monday updated its guidance saying COVID-19 can sometimes be spread by airborne transmission.It said some infections can be spread by exposure to the virus in small droplets and particles, or aerosols, that can linger in the air for minutes to hours. Monday’s update acknowledges published reports that showed limited, uncommon circumstances where people with COVID-19 infected others who were more than 6 feet away or shortly after the COVID-19-positive person left an area, the agency said.In these instances, the CDC said transmission occurred in poorly ventilated and enclosed spaces that often involved activities that caused heavier breathing, like singing or exercise.Last month, the CDC published — and then took down — its guidance warning of possible airborne transmission of the novel coronavirus. 
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