Let's talk infectious diseases, the reason for vaccines: ᴾⁿᵉᵘᵐᵒᶜᵒᶜᶜᵃˡ ᵈⁱˢᵉᵃˢᵉ

Pneumococcal disease is caused by common bacteria (Streptococcus pneumoniae) that can attack different parts of the body.

When these bacteria invade the lungs, they can cause pneumonia; when they invade the bloodstream, they can cause sepsis; and when they invade the covering of the brain, they can cause meningitis. These invasive infections are serious, often require treatment in the hospital, and can lead to death. The bacteria can also cause milder common conditions like middle-ear infection (otitis media) and sinusitis.

Pneumococcal disease is a leading cause of serious illness throughout the world. About 1.3 million persons visit emergency departments in the US each year with pneumonia, which is often caused by pneumococcal infections, and nearly 50,000 people will die from pneumonia. Fewer people will get pneumococcal meningitis or bloodstream infection, but the mortality rate for these infections is higher, even with proper treatment.

There are two main types of pneumococcal disease: non-invasive and invasive. The non-invasive form of the disease is less serious, whereas invasive is fatal in 10% of cases.

Non-invasive pneumococcal disease causes a mild infection where the s. pneumoniae bacteria can spread through the nose, throat, and upper and lower respiratory tracts. The bacteria is associated with a number of conditions: acute bronchitis, sinusitis, and otitis media (inflammation in the middle ear).

Invasive PD is more serious than the non-invasive type and occurs inside the blood or in a major organ. There are several types of invasive pneumococcal disease including pneumonia, meningitis, sepsis, bacteremia, osteomyelitis, and septic arthritis.

Treatment depends on the type of pneumococcal disease. Noninvasive pneumococcal infections may not need treatment. Invasive pneumococcal infections will require antibiotics.

The best prevention of pneumococcal disease is vaccination. While there are numerous strains of s. pneumoniae and vaccination cannot prevent all of them, pneumococcal vaccines can protect you from the most common strains.

In 1881, Louis Pasteur and U.S. Army physician George Miller Sternberg both independently discovered the Streptococcus pneumoniae bacterium that is responsible for cases of pneumonia and meningitis, as well as other illnesses.

The first whole-cell vaccine was tested on 50,000 miners in Africa in 1911. However, the date was inconclusive so the vaccine was abandoned. Another vaccine was introduced in 1945 but coincided with the advent of widespread penicillin use. With penicillin being viewed as an effective treatment for pneumococcal infections, the vaccine did not gain much traction.

One challenge in producing a pneumococcal vaccine involved determining which of the more than 90 types of pneumococcal bacteria produced the most disease. Finally, in 1977 a vaccine was licensed that protected against 14 types of pneumococcal bacteria. In 1983, Merck expanded on this work by producing a vaccine against 23 types of pneumococcal bacteria. This vaccine is still used today in adults 65 and older, as well as for individuals aged two or older who are at high risk for disease.

{You can find all the sources I used by clicking here.}