The immune system is the body’s first line of defense against pathogens such as bacteria, viruses, toxins, cancer cells, or other substances that can harm the body. If you ever come into contact with something that may compromise your health, you have an internal protector. There are two distinct components to overall immunity: the innate and adaptive systems.

Innate immunity is the type that is non-specific in nature. This means it does not pick and choose what types of pathogens to fight against. It simply gets activated and acts as a type of barrier to protect you when anything it deems harmful enters the body.

The cells involved in innate immunity are different than those involved in the second stage known as adaptive immunity. The adaptive immune system is made up of specialized cells that were developed by the body to eliminate specific pathogens and to prevent the growth of harmful substances.

While everyone has both an innate and adaptive immune system, you are not born with both. The innate system is with you from birth, but the adaptive immune system begins developing as you grow older. So how does the immune system change as you age, and at what age is the immune system strongest? Read on to learn more.

Image by MI PHAM on Unsplash: Your immune system is fully developed prior to your tenth birthday.

At what age is the immune system fully developed?

Your immune system begins to develop in the womb. The fetal environment requires some development of immunity, because there are certain maternal alloantigens that could do harm to a fetus. When you are born, you are exposed to a significantly greater number of pathogens and other substances that could trigger an immune response. This kicks your immune system into gear in terms of developmental changes.

Although the development of the immune system begins as soon as you are born, it takes roughly seven to eight years before it becomes fully developed. In the years prior, you are more susceptible to developing illnesses because your immunity is immature and cannot ward off infection as easily. That being said, the development of the immune system from birth into childhood highly depends on genetic and environmental factors.

How does the immune system change with age?

As we mentioned, immune system is made up of various cells that are designed to protect you from illness. Some act as barriers, including:  

• Skin
• Oral and gastrointestinal mucosae
• Respiratory mucosa

The barrier portion of the immune system develops in the womb and is the first wall of immunity. The cells are the second, and get called to action when something breaks through those first barriers. Immune barriers and cells change throughout a person’s life; as you age, so does your immune system.

The peak age for the immune system is roughly around the time you reach puberty. Following that, it gradually declines as you become an adult and then throughout the rest of your life. It does this because the body slowly starts to make less immune cells in the bone marrow, and other tissues and cells that are part of the immune system become slower to spring into action.

At what age does the immune system decline?

While there is no set age for when the immune system begins its decline, as mentioned above, this generally starts to happen shortly after puberty. Since people hit puberty at different times based on genetics and environmental factors, the specific age can vary by individual. The average age range for young people to hit puberty is between eight and 12 years old, with the process taking up to four years to complete.

During this time, the immune system begins to gather and produce a large repertoire of immune cells so it can be ready to fight off anything that comes its way. Basically, the body works as hard as it can to make sure that the immune system it creates will be strong throughout your life.

When the decline begins shortly after you have gone through puberty, the immune system begins to create less cells and tissues that are designed to fight off pathogens, and its action begins to slow ever so slightly each year. Even though your immunity begins to decline at such as seemingly young age, it is typically a slow process until about 60 years old, when the decline begins to more significantly affect how well your body can fight off pathogens.

Image by Eliott Reyna on Unsplash: Who has the strongest immune system? Generally, younger people have stronger immunity than elderly people.

Can you age faster than your immune system?

According to some research, the decline of the immune system isn’t exactly set in stone with your age. That means that in some cases, you could have an immune response that’s a lot faster than that of someone else your age. On the opposite side, you could also have an immune system that acts a lot “older” than your biological age.

The reasons for these discrepancies, and for the ways the decline of the immune system works, aren’t well understood. The immune system is the second most complicated bodily system after your brain, and medical researchers have yet to figure out all the ins and outs involved in the way it functions.

The good news, though, is that no matter how your immune system changes, there are always things you can do to help keep it running stronger for longer.

Featured image by Dragon Pan on Unsplash