Replacing sick employees can spread disease: Study

A new study has found that sending sick employees home and calling in a healthy external replacement can actually accelerate the spread of infection and disease.
 
The research, led by mathematical biologist Samuel Scarpino of the Santa Fe Institute, studied the effects of ‘human exchange’ in relation to the spread of disease. That is, the consequences when infected employees take sick leave and are replaced by healthy workers, something that undoubtedly raises the risk of infection for the healthy worker called in.
 
The research is particularly relevant for people in essential roles such as healthcare workers, first responders and teachers, who are often in close contact with disease and infection.
 
Scarpino, in partnership with theoretical physicist Laurent Hébert-Dufresne and the latter’s long-time collaborator Antoine Allard, tested their hypothesis by looking at 17 years’ worth of data regarding the diseases influenza and dengue. Their findings showed that human exchange does indeed accelerate outbreaks of influenza, but not so dengue, which is spread via mosquitos. “We didn’t see a strong signal in diseases where we didn’t expect it,” said Hébert-Dufresne. 
 
Hébert-Dufresne also commented on the practical implications for employees, employers and the workplace, saying, “Of course, being infinitely prudent and staying home as soon as we get infected would be ideal.”
 
“The problem is that we cannot afford to be infinitely prudent. From there comes a trade-off: staying home always slows down an epidemic at first, but eventually the fact that some responsibilities of sick workers are redistributed catches up to us once the epidemic is more prevalent. That’s when we see an acceleration.”
 
The researchers advise that a sick person should be sent home. However, rather than replacing them externally, their duties should be shared between existing workers.