Respiratory infections such as influenza (flu) and COVID-19 are mainly spread by liquid droplets that come out of the mouth and nose when a person with the virus breathes, coughs, sneezes, talks, or sings. Droplets come in a wide range of sizes, from smaller than the width of a hair to larger than a grain of sand. A few large droplets or many small droplets can contain enough virus to infect another person.

Larger droplets are heavier, and they usually fall to the ground within two meters. The majority of COVID-19 infections are spread from one person to another through larger droplets. This is why maintaining physical distance, adding physical barriers, wearing masks, and hand hygiene are all important protective measures.

 

Smaller droplets come out of the mouth and nose at the same time as larger droplets. These smaller droplets are light, and they can float in the air for a longer time. Because of this, smaller droplets may collect in enclosed spaces unless they are diluted with clean air from the outdoors or from a ventilation system. If many people are sharing a space without enough clean air, it can lead to COVID-19 infections. 

Even though COVID-19 can survive for hours or days on different surfaces, infection from contact with contaminated surfaces appears to be less common. The most common type of spread is through larger droplets from close contact with an infected person.

There is no evidence that the virus transmits through food as it is destroyed almost immediately by stomach acid. Good hand hygiene is always important for food safety. For more information, see the BCCDC page on Food Safety and COVID-19. 

For more information on how you can reduce transmission, see the BCCDC’s page on COVID-19 Prevention and Risks.