Just an abstract that gives some useful information for the model:

J Occup Environ Med. 2002 Sep; 44(9): 822-9. Related Articles, Links

Productivity losses related to the common cold.

Bramley TJ, Lerner D, Sames M.

Health-related productivity assessments typically focus on chronic conditions; however, acute conditions, particularly colds, have the potential to cause substantial health-related productivity losses because of their high prevalence in working-age groups. This article presents the findings of a study conducted to estimate productivity loss due to cold by using a telephone-administered survey that measured three sources of loss: absenteeism, on-the-job productivity, and caregiver absenteeism. Each cold experienced by a working adult caused an average of 8.7 lost work hours (2.8 absenteeism hours; 5.9 hours of on-the-job loss), and 1.2 work hours were lost because of attending to children under the age of 13 who were suffering from colds. We conclude that the economic cost of lost productivity due to the common cold approaches $25 billion, of which $16.6 billion is attributed to on-the-job productivity loss, $8 billion is attributed to absenteeism, and $230 million is attributed to caregiver absenteeism.

The costs are impressive, although the numbers seem to be low (hours per cold? or hours per week?). In any case, useful for calibrating the model and extending it to handling children + parents.