Pneumococcal disease
Pneumococcal disease is a group of infections caused by Streptococcus pneumoniae, ranging from ear infections to life-threatening pneumonia, meningitis, and bloodstream infection.
What pneumococcal disease is
Pneumococcal disease is an umbrella term for infections caused by Streptococcus pneumoniae. The bacteria can live in the nose and throat without causing illness, but they can also move into the lungs, blood, brain and spinal cord lining, ears, or sinuses. The result can be mild, serious, or rapidly life-threatening depending on where infection occurs.
How it spreads
Pneumococcus spreads through respiratory droplets and close contact with secretions from the nose or throat. Carriage is common, especially among children, and a person can carry the bacteria without feeling sick. Spread is easier in crowded settings, households, childcare, and places where respiratory infections circulate.
Types of illness
Common pneumococcal illnesses include middle-ear infection, sinus infection, and pneumonia. Invasive pneumococcal disease happens when bacteria enter normally sterile parts of the body, such as the blood or cerebrospinal fluid. Invasive disease can cause bacteremia, sepsis, meningitis, or complicated pneumonia.
Symptoms
Symptoms depend on the infection site. Pneumococcal pneumonia can cause fever, chills, cough, chest pain, fast breathing, and shortness of breath. Meningitis can cause fever, headache, stiff neck, confusion, light sensitivity, or poor feeding in infants. Bloodstream infection and sepsis can cause fever, low blood pressure, rapid heart rate, weakness, and organ stress.
Who is at higher risk
Severe disease is more likely in young children, older adults, people with weakened immune systems, people without a functioning spleen, people with chronic heart, lung, liver, kidney, or metabolic conditions, and people who smoke. Risk also rises when viral respiratory infections damage airway defenses.
Diagnosis and treatment
Diagnosis depends on the suspected infection site and can include exam findings, chest imaging, blood culture, sputum tests, cerebrospinal fluid testing, or other lab work. Antibiotics treat bacterial pneumococcal infections, but resistance patterns matter. Severe illness may need oxygen, fluids, intensive care, or treatment for complications.
Vaccines and serotypes
Pneumococcal vaccines target selected serotypes, which are versions of pneumococcus with different capsules. Conjugate vaccines train immune responses well in young children and help reduce carriage and spread of covered serotypes. Polysaccharide and newer conjugate products are used in different age and risk groups according to current schedules.
Why it matters
Pneumococcal disease sits at the intersection of ordinary respiratory carriage and severe invasive infection. Vaccination has reduced many serious cases, but the bacteria keep evolving, antibiotic resistance can complicate care, and disease burden remains high where vaccine access, diagnosis, or treatment is limited.
What public health teams watch
Surveillance tracks invasive disease, vaccine coverage, circulating serotypes, antibiotic resistance, outbreaks, and disease in high-risk groups. These data help update vaccine recommendations, monitor replacement by non-vaccine serotypes, guide treatment choices, and identify gaps in prevention.