Seeing sick people stimulates immune system

This study reported at Phys Org suggests seeing a sick person stimulates a strong immune response.

I wonder what this means for medical staff, constantly confronted with disease symptoms?

And on a lighter note, who knew just strolling through the mall while people sneeze and cough and sniffle gives my immune system a work out? See, I’m not wasting time window shopping, I’m taking preventative health action.