Table IV.

Calculating the time that an infectious aerosol shed by a patient infected with Middle East respiratory syndrome coronavirus could survive

Shed titre	Time to reach 20 virus particles
1,000,000	26 h
100,000	20 h
10,000	15 h
1000	9 h
100	4 h

The calculation assumes an infectious dose equal to severe acute respiratory syndrome coronavirus (<20 plaque-forming units) and a decay rate of 7% over 10 min in a room with no air changes.13, 16 The calculation used the following equation: P(t) = P₀e − rt, where P(t) = the amount of some quantity at time t, P₀ = initial amount at time t = 0, r = the decay rate, t = time (number of periods).