As we age, our body responds to infections differently. Even a simple cold can leave us feeling wiped out, and symptoms can drag on for weeks. This is due to changes in the immune system that naturally occur in older adults. We’re looking at what the immune system is, how to keep it working effectively and titer tests, a useful tool for determining your risk for certain infections.

What is the immune system?
Your body’s immune system is a collection of cells that travel through blood and tissue. Two parts of the immune system work together to keep you healthy.

  • Innate immune system: These cells act as scouts, responding when they detect something foreign in your body. They sound the alarm, triggering the immune response. During this process, enzymes mark germs as targets for other immune cells to attack, and blood vessels widen and become more permeable, causing redness, heat and swelling.
  • Adaptive immune system: These cells, which include antibodies as well as T and B cells, remember the specific germs they encounter. This ensures that if you are exposed to the same infection again, your immune system can mount a faster, more efficient response.

How does the immune system change with age?
During adulthood, T and B cells decline, making it more difficult for your body to fight infections. Simultaneously, the innate immune system becomes more active, causing more inflammation in the body. This can exhaust the immune system further. Because of these changes older adults can struggle to recover from cold and flu. In younger people, these infections most often remain confined to the nose or throat. For seniors, there is a greater risk of them spreading to the respiratory tract, leading to pneumonia or bronchitis. Older adults have increased risk of cells mutating to cause cancer, and the increased inflammation can damage tissue in the body, increasing the risk of heart disease, Alzheimer’s, Parkinson’s, osteoarthritis and other diseases.

What is a titer test?
A titer test is a type of blood test, which is used to determine if you’ve had previous infections or need certain immunizations. The test detects and measures the presence of certain antibodies in a person’s blood.

What infections are covered by a titer test?
Common types of titer test include MMR (measles, mumps and rubella), varicella (chickenpox and shingles), hepatitis B and rabies.

What do the test results determine?
A negative titer test means you have no immunity to a disease. A positive result indicates exposure that has established effective protection. A titer test can reveal if:

  • You’ve had a vaccine to protect against a specific disease.
  • Immunization has triggered a strong enough response to be effective.
  • You experienced a recent or past infection.
  • You currently have an infection.

How long is a titer test good for?
For illnesses such as chickenpox, measles and mumps, titer test results are usually considered valid regardless of when they were taken. Other antibody levels can drop over time, so you may need an updated test based on the medical concern.

When should you consider a titer test?
For older adults, a titer test can be effective in determining what vaccines you received decades ago, especially if no paper or digital immunization record exists. This year, a surge of seniors have opted to get MMR testing due to measles outbreaks across the country. As immunity naturally declines with age, even if you were vaccinated in the past, you may require a booster to be effectively protected. A titer test can tell you how at-risk you are for infection. 

Boost Your Immune System
There are steps you can take to prioritize your immune system as you age.

  • Prioritize sleep. Regular sleep plays a critical role in your immune system. While you sleep, your body releases proteins that help fight off infection. Sleep deprivation can lead to decreased production of protective cells. According to the Mayo Clinic, research shows that during the COVID-19 pandemic, patients who regularly got less than six hours of sleep a night came down with worse infections than those who slept more.
  • Exercise regularly. Moderate cardiovascular exercise can boost your immune system by increasing the activity of white blood cells and antibodies. Additionally, strength training helps muscles secrete myokines, which helps keep inflammation in check. The Mayo Clinic recommends creating a weekly workout plan that includes 150 minutes of cardiovascular exercise and two strength training sessions.
  • Eat a balanced diet. Avoiding ultraprocessed foods can help reduce inflammation by improving gut health. Instead opt for minimally processed, whole foods such as fish, low-fat dairy, vegetables, fruits, whole grains, legumes, nuts and seeds.
  • Keep your vaccinations updated. Vaccines are even more important as we get older. Viruses like RSV and flu can cause more severe infections. In some cases, a vaccine-inoculated immune system can block infection so effectively that you don’t experience symptoms. However, even if you do feel sick, it doesn’t mean the vaccine is not working. It’s likely helping your body clear infection more quickly so you can avoid complications. Along with regular annual vaccinations, a titer test can help determine if you require a booster for certain illnesses.
  • Get your vitamin D. If you have a vitamin D deficiency, a supplement may help boost your immune system. The vitamin boosts immune cells like T and B cells that fight off germs while also helping reduce harmful inflammation. The recommended daily amount of vitamin D is 600 IU for people 70 and under, and 800 IU for people over 70.

Sources: Mayo Clinic, Healthline