How the immune system changes with age

A slower and less precise response

Immune cells and antibodies recognize and act against harmful or foreign material, including bacteria, viruses, toxins and abnormal cells. They also react to blood or tissue from another person, which is why compatibility matters in transfusion and transplantation.

With age, the response to a new threat can be slower. This increases vulnerability to illness. The response to a vaccine may also be weaker or its protection may last for less time. These changes vary between people and do not mean that every older person has a serious immune disorder.

Healing, autoimmunity and cell surveillance

The immune response helps coordinate recovery after injury. Age-related changes, including fewer cells available for parts of the healing response, can make wounds heal more slowly. Preventing injuries therefore matters as well as treating them.

Immune regulation may also become less accurate. Autoimmune illness occurs when the body attacks its own healthy tissues. In addition, surveillance of damaged or abnormal cells becomes less effective and can contribute to an increased cancer risk. Neither autoimmunity nor cancer is an inevitable consequence of getting older.

Practical ways to reduce risk

A slower immune response makes regular prevention particularly useful. Reduce avoidable exposure and support normal immune function with vaccination, movement, adequate nutrition and attention to everyday safety.

• Discuss vaccination against influenza, COVID-19, shingles and pneumococcal disease, along with any other vaccines recommended for your age and health. Follow the schedule advised locally.
• Stay physically active at a level appropriate to your abilities and health conditions.
• Eat a varied, nutritious diet that provides enough nourishment for your needs.
• Do not smoke; if you do, seek help to stop.
• Limit alcohol and discuss whether any alcohol is suitable for you given your medicines and health.
• Reduce the risk of falls and injuries by paying attention to safe movement and hazards in your surroundings.

Notice infections and slow recovery

Seek medical advice if you suspect an infection, develop unexplained fever or have a wound that is not improving. In older adults, infection may occur without a marked fever, so a normal temperature should not be the only reason to dismiss a new illness.

Persistent or recurrent problems deserve an assessment rather than an assumption that they are just age-related. Tell your clinician about new symptoms, how long recovery is taking and your medicines. Vaccinations and healthy habits reduce risks, but they do not replace evaluation of a problem that has already developed.