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Pneumococcus

Pneumococcus, scientifically known as Streptococcus pneumoniae, is a spherical bacterium commonly found in the upper respiratory tract, particularly among young children. It can be highly infectious and is transmitted through respiratory droplets. While there are over ninety strains of pneumococci, only a select few are responsible for severe illnesses, including pneumonia, sepsis, and meningitis. Non-invasive pneumococcal diseases, such as bronchitis and otitis media, generally cause milder symptoms and can often be managed at home. However, invasive infections are more serious and can lead to life-threatening conditions, particularly affecting those under two years of age, adults over sixty-five, and individuals with weakened immune systems.

Pneumonia, the most common invasive pneumococcal disease, affects hundreds of thousands of Americans annually, with a notable percentage resulting in fatalities. Sepsis and meningitis, while less frequent, carry higher mortality rates and require urgent medical attention and antibiotics. Vaccination plays a crucial role in prevention, with several vaccines available, including the pneumococcal conjugate vaccine (PCV13) and the polysaccharide vaccine (PPSV23), both targeted at high-risk populations. Understanding pneumococcus and its associated diseases is essential for recognizing and addressing potential health risks.

Full Article

Pneumococcus (plural pneumococci), also known as Streptococcus pneumoniae, is a highly infectious bacterial microorganism that can cause a number of serious illnesses, some of which can be life-threatening. The bacterium is most commonly found in the human respiratory tract and can be transmitted from person to person through droplets dispersed in the air. More than one hundred pneumococcal serotypes exist, but only a few cause the most serious illnesses, such as pneumonia, sepsis, and meningitis.

Overview

Pneumococcus is a spherical-shaped bacterium usually found in the upper respiratory tract, especially among young children. The bacterium's scientific name is Streptococcus pneumoniae, from the Greek words strepto, meaning "twisted," and coccus, meaning "berry." The term pneumoniae refers to the bacterium's tendency to attack the lungs and cause pneumonia.

More than one hundred pneumococcal serotypes exist, most of which cause non-invasive infections. These occur outside major organs or the bloodstream and are usually less serious. Invasive infections occur within major organs or the bloodstream, places that are usually free from bacteria. These are more serious illnesses and can be fatal at times.

Pneumococcal diseases occur most often in children under the age of five years, adults older than fifty years, and people whose immune systems have been weakened by other diseases or medical conditions or by smoking. Pneumococcal diseases have remained a significant global cause of illness and death.

Common non-invasive pneumococcal diseases include bronchitis, an infection of the bronchial tubes in the lungs; otitis media, a middle-ear infection and a common cause of earaches in children; and sinusitis, an infection in the cavities near the nasal passages. Symptoms of these infections and treatment depend on the type and extent of the infection;  mild infections can be treated with rest, fluids, and over-the-counter medicines, but more severe bacterial pneumococcal infections often require medical evaluation and may need antibiotics.

The more serious invasive infections affect the lungs, the bloodstream, or the membranes surrounding the brain and spinal cord. The most common of these is pneumonia, an infection of the lungs. The Centers for Disease Control and Prevention in the United States recorded about 1.2 million emergency-department visits in 2022 because of pneumonia from an infectious organism, with about 41,210 deaths reported in 2023.

Blood infections include the less serious bacteremia and a potentially life-threatening form of blood poisoning called sepsis. A pneumococcal infection that affects the lining of the brain or spinal cord is meningitis. While these forms of infection are less common than pneumonia, they can be far more deadly. Pneumococcal blood infections and meningitis occur more often in adults. They can be treated with bacteria-killing antibiotics and may require hospitalization.

Several vaccines are available to prevent pneumococcal infection. In the United States, the CDC recommends routine pneumococcal vaccination with PCV15 or PCV20 for all children younger than five years and with PCV15, PCV20, or PCV21, depending on prior vaccination history, for adults fifty years or older.


Bibliography

“About Pneumococcal Disease.” Centers for Disease Control and Prevention, 24 Feb. 2026, cdc.gov/pneumococcal/about/index.html. Accessed 17 Mar. 2026.

Balch, Bridget. "Sepsis Is the Third Leading Cause of Deaths in U.S. Hospitals. But Quick Action Can Save Lives." Association of American Medical Colleges, 10 Oct. 2023, www.aamc.org/news/sepsis-third-leading-cause-death-us-hospitals-quick-action-can-save-lives. Accessed 16 Mar. 2026. 

“Clinical Overview of Pneumococcal Disease.” Centers for Disease Control and Prevention, 25 Feb. 2026, www.cdc.gov/pneumococcal/hcp/clinical-overview/index.html. Accessed 16 Mar. 2026.

Henriques-Normark, Birgitta, and Elaine I. Tuomanen. "The Pneumococcus: Epidemiology, Microbiology, and Pathogenesis." Cold Spring Harbor Perspectives in Medicine, 2013, perspectivesinmedicine.cshlp.org/content/3/7/a010215. Accessed 16 Mar. 2026.

"Meningitis." Mayo Clinic, 17 Oct. 2024, www.mayoclinic.org/diseases-conditions/meningitis/home/ovc-20169520. Accessed 16 Mar. 2026.

“Pneumococcal Vaccine Recommendations.” Centers for Disease Control and Prevention, 25 Feb. 2026, www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/index.html. Accessed 16 Mar. 2026.

"Pneumonia." Centers for Disease Control and Prevention, 22 July 2025, www.cdc.gov/nchs/fastats/pneumonia.htm. Accessed 16 Mar. 2026. 

"Pneumonia." Mayo Clinic, 13 June 2020, www.mayoclinic.org/diseases-conditions/pneumonia/home/ovc-20204676. Accessed 16 Mar. 2026.

Sandoiu, Ana. "How Preventable is Sepsis-Related Death?" Medical News Today, 12 Mar. 2019, www.medicalnewstoday.com/articles/324687. Accessed 16 Mar. 2026. 

"Sepsis." Mayo Clinic, 10 Feb. 2023, www.mayoclinic.org/diseases-conditions/sepsis/home/ovc-20169784. Accessed 16 Mar. 2026.

Full Article

Pneumococcus (plural pneumococci), also known as Streptococcus pneumoniae, is a highly infectious bacterial microorganism that can cause a number of serious illnesses, some of which can be life-threatening. The bacterium is most commonly found in the human respiratory tract and can be transmitted from person to person through droplets dispersed in the air. More than one hundred pneumococcal serotypes exist, but only a few cause the most serious illnesses, such as pneumonia, sepsis, and meningitis.

Overview

Pneumococcus is a spherical-shaped bacterium usually found in the upper respiratory tract, especially among young children. The bacterium's scientific name is Streptococcus pneumoniae, from the Greek words strepto, meaning "twisted," and coccus, meaning "berry." The term pneumoniae refers to the bacterium's tendency to attack the lungs and cause pneumonia.

More than one hundred pneumococcal serotypes exist, most of which cause non-invasive infections. These occur outside major organs or the bloodstream and are usually less serious. Invasive infections occur within major organs or the bloodstream, places that are usually free from bacteria. These are more serious illnesses and can be fatal at times.

Pneumococcal diseases occur most often in children under the age of five years, adults older than fifty years, and people whose immune systems have been weakened by other diseases or medical conditions or by smoking. Pneumococcal diseases have remained a significant global cause of illness and death.

Common non-invasive pneumococcal diseases include bronchitis, an infection of the bronchial tubes in the lungs; otitis media, a middle-ear infection and a common cause of earaches in children; and sinusitis, an infection in the cavities near the nasal passages. Symptoms of these infections and treatment depend on the type and extent of the infection;  mild infections can be treated with rest, fluids, and over-the-counter medicines, but more severe bacterial pneumococcal infections often require medical evaluation and may need antibiotics.

The more serious invasive infections affect the lungs, the bloodstream, or the membranes surrounding the brain and spinal cord. The most common of these is pneumonia, an infection of the lungs. The Centers for Disease Control and Prevention in the United States recorded about 1.2 million emergency-department visits in 2022 because of pneumonia from an infectious organism, with about 41,210 deaths reported in 2023.

Blood infections include the less serious bacteremia and a potentially life-threatening form of blood poisoning called sepsis. A pneumococcal infection that affects the lining of the brain or spinal cord is meningitis. While these forms of infection are less common than pneumonia, they can be far more deadly. Pneumococcal blood infections and meningitis occur more often in adults. They can be treated with bacteria-killing antibiotics and may require hospitalization.

Several vaccines are available to prevent pneumococcal infection. In the United States, the CDC recommends routine pneumococcal vaccination with PCV15 or PCV20 for all children younger than five years and with PCV15, PCV20, or PCV21, depending on prior vaccination history, for adults fifty years or older.


Bibliography

“About Pneumococcal Disease.” Centers for Disease Control and Prevention, 24 Feb. 2026, cdc.gov/pneumococcal/about/index.html. Accessed 17 Mar. 2026.

Balch, Bridget. "Sepsis Is the Third Leading Cause of Deaths in U.S. Hospitals. But Quick Action Can Save Lives." Association of American Medical Colleges, 10 Oct. 2023, www.aamc.org/news/sepsis-third-leading-cause-death-us-hospitals-quick-action-can-save-lives. Accessed 16 Mar. 2026. 

“Clinical Overview of Pneumococcal Disease.” Centers for Disease Control and Prevention, 25 Feb. 2026, www.cdc.gov/pneumococcal/hcp/clinical-overview/index.html. Accessed 16 Mar. 2026.

Henriques-Normark, Birgitta, and Elaine I. Tuomanen. "The Pneumococcus: Epidemiology, Microbiology, and Pathogenesis." Cold Spring Harbor Perspectives in Medicine, 2013, perspectivesinmedicine.cshlp.org/content/3/7/a010215. Accessed 16 Mar. 2026.

"Meningitis." Mayo Clinic, 17 Oct. 2024, www.mayoclinic.org/diseases-conditions/meningitis/home/ovc-20169520. Accessed 16 Mar. 2026.

“Pneumococcal Vaccine Recommendations.” Centers for Disease Control and Prevention, 25 Feb. 2026, www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/index.html. Accessed 16 Mar. 2026.

"Pneumonia." Centers for Disease Control and Prevention, 22 July 2025, www.cdc.gov/nchs/fastats/pneumonia.htm. Accessed 16 Mar. 2026. 

"Pneumonia." Mayo Clinic, 13 June 2020, www.mayoclinic.org/diseases-conditions/pneumonia/home/ovc-20204676. Accessed 16 Mar. 2026.

Sandoiu, Ana. "How Preventable is Sepsis-Related Death?" Medical News Today, 12 Mar. 2019, www.medicalnewstoday.com/articles/324687. Accessed 16 Mar. 2026. 

"Sepsis." Mayo Clinic, 10 Feb. 2023, www.mayoclinic.org/diseases-conditions/sepsis/home/ovc-20169784. Accessed 16 Mar. 2026.

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