Calculates the pretest probability over time, assuming the individual does not develop symptoms, by taking into account the distribution of incubation periods (defined as the time from exposure to symptom onset).

adjust_pretest(pre0, asympt, days = 14, mu = 1.63, sigma = 0.5)

Arguments

pre0

Initial pretest probability (on day of exposure)

asympt

The proportion of positive patients who would be expected not to ever develop symptoms (true asymptomatic patients).

days

Days since exposure for calculation range

mu

The mean of a lognormal distribution that approximates the incubation period for COVID-19. E.g. 1.63 (see reference).

sigma

The standard deviation of a lognormal distribution that approximates the incubation period for COVID-19. E.g. 0.5 (see reference).

Value

pretest probability by day (time series)

References

See McAloon et al. https://bmjopen.bmj.com/content/10/8/e039652/