Does your immune system weaken as you age?

Yes, your immune system weakens as you age, and it happens to everyone. Research shows that age-associated changes to the immune system can make older adults (aged 65+) more vulnerable to infections.

The immune system is made up of many different types of cells that work together to detect and fight threats.

Over time, two types of white blood cells, T cells and B cells, become less effective at identifying new threats and responding to ones the body has encountered before.

• T cells help coordinate the immune response and attack infected cells directly.
• B cells produce antibodies, which are proteins that target specific threats.

This doesn't mean the immune system stops working.

As you age, your immune system continues to function, but it becomes less responsive, meaning reactions to new infections can take longer. The immune memory you’ve built up from past illnesses or vaccines may not hold as strongly, and the overall immune response becomes less efficient, even in people who are otherwise healthy.

This natural age-related weakening of the immune system over time is commonly referred to as immune aging, or immunosenescence.

If I've been healthy my whole life, am I still at risk of a weakened immune system?

Immune aging happens to everyone and it doesn't reflect your lifestyle choices or habits. Here’s a useful way to think about it: Changes in vision can happen even if you've always taken good care of your eyes. You may eat well, protect your eyes from sun damage, get regular check-ups, and still find that you need reading glasses as you age. That shift comes down to biology and how the body changes with age.

The same is true for the immune system.

Healthy habits including good nutrition, regular movement, and adequate sleep can help reduce many health risks. These habits can help slow the gradual shift in immune function that comes with age, but it does not stop it.

Because age is an independent risk factor for infections, you can be both healthy and increasingly vulnerable to certain illnesses at the same time.

What can you do to support your immune health as you age?

No single habit or intervention is a complete solution, but several evidence-based approaches may help support immune function over time, and they work better together.

• Vaccination: Keeping vaccines up to date is one of the most direct ways to strengthen the immune system's ability to respond to specific threats, especially as the immune response becomes less precise with age. Learn more about how vaccines work.
• Sleep: There's a well-established connection between sleep and immune function. During sleep, the body carries out important immune-related processes. Consistently poor sleep can affect how well the immune system responds.
• Nutrition: Diets rich in protein, antioxidants, and anti-inflammatory foods (e.g., vegetables, fruit, whole grains, healthy fats) provide the building blocks the immune system needs to function effectively.
• Physical activity: Regular, moderate exercise has been shown to support immune response. It doesn't have to be intense; consistent movement is what matters.
• Stress management and social connection: Both chronic stress and social isolation have documented effects on immune health. Managing stress and staying connected to others are underappreciated but meaningful contributors.
• Regular healthcare check-ins: Staying current on screenings and preventive care helps catch changes early and ensures your overall health plan reflects where you are now, not where you were ten years ago.

These strategies work together. Healthy habits support your immune system overall, while vaccines provide targeted protection.

What vaccines are recommended as you get older?

One of the most practical responses to immune aging is making sure vaccinations are up to date. This includes ones you may not have thought about since childhood, as well as newer ones designed specifically for older adults.

Some vaccines are formulated specifically for older adults with aging immune systems. High-dose influenza vaccines, for example, are designed to prompt a stronger immune response in older adults, recognizing that the standard dose may not be as effective.

General age-milestone recommendations from the CDC Advisory Committee on Immunization Practices (ACIP) include:

• From age 50: Shingles vaccine (recommended as a two-dose series), and a pneumococcal vaccine.
• From ages 50-74: RSV vaccine for adults at increased risk.
• From age 65: High-dose or adjuvanted flu vaccine; the updated COVID-19 vaccine; a pneumococcal vaccine depending on previous pneumococcal vaccination history.
• From age 75: A single RSV vaccine for all adults.

These thresholds reflect the points at which immune changes warrant specific protective action.

A healthcare provider is the best person to help you understand which vaccines are relevant to you based on your age, health history, and what you may already have received. Learn more about discussing vaccines with your healthcare provider.