Understanding Pneumococcal Disease

Pneumococcal disease is a bacterial infection that can range from a mild ear infection to a life-threatening illness. Many people carry the bacteria in their nose and throat without ever getting sick, yet each year it sends thousands to the hospital. Learning what this disease is, how it works, who it affects, and how it is treated can help you protect yourself and your loved ones.¹

What is pneumococcal disease?

Pneumococcal disease is the name for any infection caused by a type of bacteria called Streptococcus pneumoniae, often shortened to pneumococcus. These bacteria can lead to many different kinds of infections. Some are mild, like ear infections and sinus infections. Others are much more serious, such as pneumonia (a lung infection), bacteremia (a bloodstream infection), and meningitis (an infection of the lining that covers the brain and spinal cord).¹

The bacteria spread from person to person through direct contact with spit or mucus, like the droplets released when someone coughs or sneezes. Here is something surprising: Many healthy people carry pneumococcus in their nose and throat and never get sick at all. It usually lives there quietly. The trouble starts when the bacteria move into parts of the body where they do not belong.^1,2

How does pneumococcal disease affect the body?

Normally, pneumococcus just sits in the nasopharynx, which is the area at the back of your nose and throat. Your immune system keeps it in check. But sometimes the bacteria travel to places that should be germ-free, such as the lungs, the bloodstream, or the fluid around the brain. When that happens, an infection begins and can spread quickly.²

Pneumococcus is good at causing harm because of a slippery outer coating called a capsule. This capsule acts like a shield. It helps the bacteria hide from the white blood cells that would normally swallow and destroy them. Because the immune system has a harder time fighting back, the bacteria can multiply and make a person very sick.²

When the infection reaches the blood or brain, doctors call it invasive pneumococcal disease, and it can be very serious. In adults older than 65, this kind of serious infection can be fatal.²

Who is at risk for pneumococcal disease?

Anyone can get pneumococcal disease, but some people face a much higher risk than others. Young children under age 5 and older adults are the most likely to become seriously ill. People with certain health conditions, such as diabetes, heart disease, lung disease, or a weakened immune system, are also at greater risk.¹

Age matters a great deal. For many years, health officials mainly recommended vaccines for adults 65 and older. That changed in October 2024. The Advisory Committee on Immunization Practices (ACIP), which advises the United States government, lowered the age and now recommends pneumococcal vaccination for all adults 50 years and older.³

In other words, if you are 50 or older, you are now part of the group that health experts say should be protected with the pneumococcal vaccine. Experts made this change to reach more people, make the rules simpler, and help close gaps in who gets sick.^1,4

Vaccines are the best way to prevent the disease. Talk with your doctor about which one is right for you.

How is pneumococcal disease treated?

When someone does get pneumococcal disease, doctors treat it with antibiotics, which are medicines that kill bacteria. First, the doctor may run tests to find out exactly which bacteria are causing the illness. For serious infections, they may take samples of blood or the fluid around the brain and spinal cord and send them to a lab.¹

Testing is important for another reason, too. Some pneumococcal bacteria have become resistant to certain antibiotics, meaning those drugs no longer work well against them. Lab tests show doctors which antibiotic will fight the infection best, so treatment is faster and more likely to succeed.¹

Protect yourself

Pneumococcal disease is a common but sometimes very serious infection caused by bacteria many of us carry without knowing. It can range from a mild ear infection to a dangerous illness in the lungs, blood, or brain. Young children, people with certain health problems, and now adults 50 and older are most at risk.^1-4

Antibiotics can treat the disease, but vaccines remain the best way to stop it before it starts. If you are 50 or older, ask your doctor whether a pneumococcal vaccine is right for you.^3,4