As with any other poison, viruses are usually more dangerous in larger amounts. Small initial exposures tend to lead to mild or asymptomatic infections, while larger doses can be lethal.
Despite the evidence for the importance of viral dose, many of the epidemiological models being used to inform policy during this pandemic ignore it. This is a mistake.
People should take particular care against high-dose exposures, which are most likely to occur in close in-person interactions — such as coffee meetings, crowded bars and quiet time in a room with Grandma — and from touching our faces after getting substantial amounts of virus on our hands. In-person interactions are more dangerous in enclosed spaces and at short distances, with dose escalating with exposure time. For transient interactions that violate the rule of maintaining six feet between you and others, such as paying a cashier at the grocery store, keep them brief — aim for “within six feet, only six seconds.”
(https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html)
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