Why do my colds last longer when I smoke?

Because local respiratory defences (cilia, mucus, macrophages) are compromised. Germs stay longer, inflammation persists, healing is slower.

Does tobacco really worsen flu?

Yes. Increased risk of post-flu pneumonia, longer and more severe forms. Annual flu vaccination is particularly recommended for smokers.

Several studies showed smokers had more severe forms of COVID-19 (more hospital and ICU admissions). Vaccine response is also slightly weaker in them.

Does second-hand smoke have an immune effect too?

Yes, particularly in exposed children: more otitis, more bronchiolitis, more asthma. See our article on second-hand smoke and children.

If I vape, is my immunity also affected?

Vaping seems to have a much smaller impact on the respiratory immune system. No marked effect on cilia or alveolar macrophages.

Smoking and the immune system: why you catch more colds and infections when you smoke

Tobacco weakens the immune system. More colds, more bronchitis, weaker vaccine response. Mechanisms and recovery after quitting.

May 14, 2026 Aria

If you smoke and feel like you fall ill more often than your non-smoker friends, that is not just a feeling. Tobacco weakens the immune system at several levels. More respiratory infections, worse flus, less effective vaccines, and slowed wound healing.

How smoke disrupts your defences

The immune system is an orchestra — white blood cells, antibodies, cytokines, mucous barriers. Cigarette smoke knocks the score off-key on several lines at once.

+ 2 to 4 respiratory infections per year more in regular smokers, compared with comparable non-smokers.

Epidemiological cohort studies

Vaccines: less protection in smokers

Several studies have measured the antibody response to standard vaccines:

A smoker has an immune system working on two fronts at once — handling chronic smoke and defending against infection. Inevitably, both jobs are done less well.

Selon les pneumologues

Which infections rise?

Myth vs reality

Recovery after quitting

3 days bronchial cilia restart their cleaning work (cough possible).
2 weeks to 1 month mucus production normalises, oral flora rebalances.
3 to 6 months pulmonary immune function clearly improves.
1 to 2 years vaccine response approaches that of a non-smoker.

In United Kingdom

Your questions

Why do my colds last longer when I smoke?

Because local respiratory defences (cilia, mucus, macrophages) are compromised. Germs stay longer, inflammation persists, healing is slower.
Does tobacco really worsen flu?

Yes. Increased risk of post-flu pneumonia, longer and more severe forms. Annual flu vaccination is particularly recommended for smokers.
And COVID-19?

Several studies showed smokers had more severe forms of COVID-19 (more hospital and ICU admissions). Vaccine response is also slightly weaker in them.
Does second-hand smoke have an immune effect too?

Yes, particularly in exposed children: more otitis, more bronchiolitis, more asthma. See our article on second-hand smoke and children.
If I vape, is my immunity also affected?

Vaping seems to have a much smaller impact on the respiratory immune system. No marked effect on cilia or alveolar macrophages.

sources

Sopori M, Effects of cigarette smoke on the immune system, Nature Reviews Immunology, 2002.
Gonçalves RB et al., Impact of smoking on inflammation: overview of molecular mechanisms, Inflammation Research, 2011.
Société de Pneumologie de Langue Française, Tobacco and respiratory infections, 2023 dossier.
US Surgeon General, The Health Consequences of Smoking — 50 Years of Progress, 2014, immunity chapter.