The economic costs of perceived reduced immune fitness in the Netherlands

Background: Immune fitness has been defined as a state where an individual's immune system is resilient, having an inbuilt capacity to adapt to challenges by establishing, maintaining, and regulating an appropriate immune response in order to promote health and prevent and resolve disease [1]. Perceived reduced immune fitness can be a possible reason for absenteeism (staying home from work) or presenteeism (attending work despite health problems, possibly with reduced work performance).

Objective: The purpose of the current study was to investigate the impact of reduced immune fitness on absenteeism and presenteeism at work, and the estimated associated costs for the Dutch economy.

Methods: Dutch adults were recruited via Facebook to complete an online survey [2]. Participants could indicate whether in 2019 (i.e. pre-COVID-19) they were employed (owner or employee). Absenteeism and presenteeism related to perceived reduced immune fitness were assessed. To this end, questions were adapted from a recent study examining the cost of workplace hangovers and intoxication to the UK economy [3]. Questions concerned the number of days in 2019 that participants (a) did not work because they experienced reduced immune fitness and (b) did work although they experienced reduced immune fitness. With regard to presenteeism, they could further indicate, in comparison to a regular working day, how well they performed at work on days when they experienced reduced immune fitness. This was done by rating their performance on a scale ranging from 0% (compared to a regular day I achieved nothing/did not work) to 100% (my work was absolutely not influenced by experiencing reduced immune fitness). Statistics Netherlands provided information on the average Dutch income. Perceived immune fitness was assessed with the immune status questionnaire [1]. In line with Bhattacharya's method [3], the economic costs of absenteeism and presenteeism due to reduced immune fitness were calculated.

Results: Data of N=466 participants with a mean (SD) age of 37 (15.2) years old (range: 18-65 years old), 67.4% female, was evaluated. Overall, 4.4 days of absenteeism, 27.1 days of presenteeism, and a 21% reduction of performance level were reported for presenteeism days. Females, higher educated, and older participants reported significantly higher rates of absenteeism and presenteeism, and lower performance levels on days working with reduced immune fitness. Significant correlations (p<0.05) were found between perceived immune fitness and the number of absenteeism (r = -0.350) and presenteeism days (r = -0.339). The estimated economic cost of absenteeism (€6.8± 0.064 billion euro) and presenteeism (€8.8 ± 0.083 billion euro) sum up to a total cost of €15.6± 0.147 billion euro.

Conclusions: Perceived reduced immune fitness has a significant negative impact on work performance, expressed in both absenteeism and presenteeism. Based on the present sample, the associated annual costs for the Dutch economy for 2019 were estimated at 15.6 billion Euro. These high costs warrant further investigation. A large nationally representative sample should be conducted to verify these findings and yield a more accurate estimate of the associated economic costs of perceived reduced immune fitness.