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Pneumococcal Infections


Larry M. Bush

, MD, FACP, Charles E. Schmidt College of Medicine, Florida Atlantic University

Last full review/revision Mar 2021| Content last modified Mar 2021
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Pneumococcal infections are caused by the gram-positive, sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up) Streptococcus pneumoniae (pneumococci). These bacteria commonly cause pneumonia, meningitis, sinusitis, and middle ear infection.

  • Pneumococcal bacteria are dispersed in the air when infected people cough or sneeze.

  • Pneumococcal infections usually cause fever and a general feeling of illness, with other symptoms depending on which part of the body is infected.

  • Diagnosis may be based on symptoms or identification of the bacteria in samples of infected material.

  • Young children are routinely vaccinated against these infections, and vaccination is also recommended for all people 65 years of age and older and all people at high risk.

  • Penicillin or another antibiotic is usually effective treatment.

(See also Overview of Bacteria.)

There are more than 90 types of pneumococci. However, most serious infections are caused by only a few types.

Pneumococci commonly reside in the upper respiratory tract of healthy people, their natural host, particularly during the winter and early spring. The bacteria spread to other people when they do the following:

  • Inhale infected droplets dispersed by sneezing or coughing

  • Come in close contact with an infected person

Spread is more likely among certain populations of people, such as military personnel and homeless people. Spread is also more likely to occur among self-contained groups of people, such as people who live, stay, or work in nursing homes or long-term care facilities, hospital wards, prisons, military bases, universities or schools, shelters for the homeless, or day care centers.

Risk factors

Certain conditions increase the risk of developing and the severity of pneumococcal infections:

Influenza and chronic bronchitis may damage the lining of respiratory tract and thus make it easier for pneumococcal bacteria to cause infection.

Also, older people, even if healthy, tend to have more severe symptoms and complications when they get a pneumococcal infection.

Symptoms and Diagnosis

Symptoms of pneumococcal infections vary depending on the site of the infection.

Most pneumococcal infections occur in the

The bacteria may also spread to and through the bloodstream (called bacteremia). Infections may occur in the tissues covering the brain and spinal cord (meningitis) or, less often, in heart valves (endocarditis), bones, joints, or the abdominal cavity.

Pneumococcal pneumonia

Often, symptoms of pneumococcal pneumonia begin suddenly. People have fever, chills, a general feeling of illness (malaise), shortness of breath, and a cough. The cough brings up sputum that is rust-colored.

Commonly, sharp, stabbing chest pains occur on one side. Deep breathing and coughing make the pains worse. In about 40% of people, fluid accumulates between the layers of tissue that cover the lungs (called pleural effusion). Pleural effusion may contribute to chest pain and make breathing difficult.

Chest x-rays are taken to look for signs of pneumonia. Doctors take a sample of sputum and examine it under a microscope. A sample of sputum, pus, or blood may be sent to a laboratory to grow (culture) bacteria. Pneumococcal bacteria are easily identified. They are also tested to see which antibiotics are effective (a process called susceptibility testing).

Pneumococcal meningitis

People with pneumococcal meningitis have fever, headache, and a general feeling of illness (malaise). They have a stiff neck that makes lowering the chin to the chest painful and difficult, but this problem is not always obvious early in the disease.

Unlike older children and adults, most infants with meningitis do not have a stiff neck. They may only be reluctant to eat and be irritable or sluggish.

Pneumococcal meningitis may lead to complications, such as

  • Hearing loss (in up to 50% of people)

  • Seizures

  • Learning disabilities

  • Mental dysfunction

The diagnosis of pneumococcal meningitis requires a spinal tap (lumbar puncture) to obtain a sample of the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). The sample is checked for signs of infection, such as white blood cells and bacteria.

Pneumococcal otitis media

Pneumococcal otitis media causes ear pain and a red, bulging eardrum or pus behind the eardrum. These infections can cause

Pneumococcal bacteria causes about 30 to 40% of all cases of otitis media in children. Pneumococcal otitis media commonly recurs.

The diagnosis of pneumococcal otitis media is usually based on symptoms and results of a physical examination. Cultures and other diagnostic tests are usually not done.

Pneumococcal sinusitis

Pneumococcal sinusitis most commonly affects the sinuses located in the cheekbones (the maxillary sinuses) and the sinuses located on either side of the nasal cavity (the ethmoid sinuses). The infection causes sinus pain and pus discharged from the nose. The infection may become chronic. The infection may extend into the skull and cause complications such as the following:

A doctor bases the diagnosis of sinusitis on the typical symptoms. A computed tomography (CT) scan is done when people have symptoms of complications or when people have chronic sinusitis.

Pneumococcal bacteremia

Pneumococcal bacteremia is bacteria in the bloodstream. It may be the primary infection, or it may accompany any of the other pneumococcal infections. When bacteremia occurs, it may lead to other infections, such as in the joints (infectious arthritis), the lining of the heart (endocarditis), or the tissues covering the spinal cord and brain (meningitis).

If bacteremia is suspected, doctors usually take a sample of blood so they can try to grow (culture) the bacteria in the laboratory and identify it.

Despite antibiotic treatment, pneumococcal bacteremia often causes death, especially in older people, people who have disorders that weaken their immune system, or people who have no spleen.

Prevention of Pneumococcal Infections

Pneumococcal infections can be prevented with vaccines and, for certain people, antibiotics.


For more information, see also Pneumococcal Vaccine and the vaccine schedules for children and adults from the Centers for Disease Control and Prevention (CDC).

Two types of pneumococcal vaccines are available:

  • A conjugate vaccine (PCV13) that protects against 13 types of pneumococci

  • A polysaccharide vaccine (PPSV23) that protects against 23 types of pneumococci

The vaccine schedules vary depending on the person's age and medical conditions.

PCV13 is recommended for

  • All children 2 months through 6 years of age as part of the routine childhood vaccination schedule

  • People aged 65 years and over who have a condition that weakens their immune system, cerebrospinal fluid leak, or cochlear implant and who have not previously received PCV13

  • People aged 65 years and over who do not have any of the above conditions, provided they discuss the relative risks and benefits of the vaccine with their doctor

  • People aged 6 to 64 who have certain high-risk conditions

PPSV23 is recommended for


If children under 5 years old do not have a spleen or if their spleen is not functioning, they may be given antibiotics (such as penicillin) in addition to the vaccine. In such cases, antibiotics may be continued throughout childhood and into adulthood.

Treatment of Pneumococcal Infections

  • Antibiotics

Penicillin (or the related drugs, ampicillin and amoxicillin) is used for most pneumococcal infections. It is usually taken by mouth but, if the infection is severe, may be given intravenously.

Pneumococci that are resistant to penicillin are becoming more common. Thus, other antibiotics, such as ceftriaxone, cefotaxime, fluoroquinolones (such as levofloxacin), vancomycin, lefamulin, or omadacycline, are often used. Vancomycin is not always effective against meningitis caused by pneumococci. Thus, people with meningitis are usually given ceftriaxone or cefotaxime, rifampin, or both, as well as vancomycin.

More Information

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

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Chickenpox is a highly contagious viral infection that tends to be fairly mild in most cases. Which of the following groups has the lowest risk of complications from chickenpox?
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