• Smokers are definitely more likely to experience the adverse consequences of flu infections.
• It may be helpful for smokers to take vitamin C to help ward off colds and flu.
• In smokers, the cilia (the tiny "brooms" of the airways which clear the lungs) are already damaged. An important defense mechanism of the airways is therefore compromised.
• A respiratory assault (from a flu virus) can further damage the surface of bronchi, leading to bronchitis. Secondary bacterial infection is usual in this context.

Reviewed (2006) by Dr Jane Yeats MBChB, BSc(Med)(Hons)Biochem, FCPathSA(Virology).