Immune System & Smoking

Your immune system protects you from harmful viruses and bacteria. It also helps your body heal from injuries and wounds. But when your immune system is weakened, it is less able to fight off infections and diseases.

Smoking harms and weakens parts of the immune system. This increases your chances of getting sick or dying. Someone who is immunocompromised has a weakened immune system and faces even more health risks if they smoke.

Whether or not you are immunocompromised, quitting smoking can improve your health.

Why does smoking harm the immune system?

Cigarette smoke contains more than 7,000 chemicals. They damage parts of the immune system. Some chemicals in cigarette smoke that damage the immune system include:

• Toxins like carbon monoxide and ammonia
• Carcinogens (substances that can cause cancer)
• Other health-harming chemicals

What are the health effects of smoking on the immune system?

Your risks for many kinds of diseases related to the immune system increase if you smoke. Risks include:

• Viral and bacterial infections (like Covid-19, the flu, pneumonia, and tuberculosis)
• Bacterial meningitis (a disease that attacks the membranes covering the brain and spinal cord)
• Infections after surgery
• Problems with wound healing
• Rheumatoid arthritis (an autoimmune disease)
• Crohn’s disease (a serious digestive system disease)
• Cancer

Being around cigarette smoke can hurt other people’s immune systems, too. Babies and children who are exposed to secondhand smoke are more likely to get serious diseases like bronchitis, bronchiolitis, and pneumonia.

Long-term smoking can cause permanent damage to your immune system. The bottom line is that quitting smoking is very important for your health.

How can quitting smoking improve the immune system?

When you quit smoking, your immune system is no longer exposed to chemicals that hurt it. After you quit, you will be less likely to get sick from some diseases.

Quitting smoking helps the immune system heal wounds better. Quitting smoking improves blood flow to wounds. This lets nutrients, minerals, and oxygen reach the wound and helps it heal.

Besides smoking, what conditions can cause a weakened immune system?

Several conditions can cause a weakened immune system. They include:

• Health conditions, including HIV/AIDS, asthma, cystic fibrosis, leukemia or lymphoma
• Autoimmune diseases, like lupus, rheumatoid arthritis, and type 1 diabetes
• Medical treatment, including cancer treatments, long-term use of corticosteroids and therapies like biologics and disease-modifying antirheumatic drugs (DMARDS)
• Organ or bone marrow transplant

If you are immunocompromised and smoke, you are at even higher risk of smoking-related and other illnesses. Quitting smoking is very important for your health if you are immunocompromised.