Smoking has substantial local and systemic adverse effects on the immune system, respiratory tract and skin and soft tissues. Smokers are at increased risk of invasive pneumococcal disease, pneumonia, periodontitis, surgical infections, tuberculosis, influenza and meningococcal disease.

The results of several studies indicate that smokers with periodontitis or tuberculosis suffer more‐severe disease. Data on the impact of smoking in sepsis and pneumonia are controversial and limited, and systematic data regarding the outcome of the majority of infections in smokers are scarce. Abundant data indicate that children exposed to environmental tobacco smoke (ETS) suffer from more‐severe infections.

However, information regarding the effects of ETS on the outcome of infections in adul...