Much like Haemophilus influenzae type b (Hib), pneumococcal bacteria (Streptococcus pneumoniae) affect the most defenseless of the population (infants, toddlers and the elderly). The diseases caused by pneumococcus include meningitis, bloodstream infections and pneumonia. The pneumococcal vaccine was first introduced for use in all infants in the United States in 2000. Before the vaccine, every year pneumococcus caused about 700 cases of meningitis, 17,000 cases of bloodstream infections and 71,000 cases of pneumonia.
Infants and young children are at greatest risk of serious infection because they are unable to develop immunity to the sugar (or polysaccharide) that coats the bacteria, something that older children can do when they are more than 2 years of age.
An ounce of prevention is worth a pound of cure
In the 1940s all of the strains of pneumococcus were sensitive to the antibiotic, penicillin. However, over time many strains of pneumococcus have become resistant not only to penicillin, but also to the broader-spectrum antibiotics developed to combat bacterial infections. Strains of pneumococcus have now been identified that are highly resistant to most antibiotics. Our reliance on and overuse of antibiotics have led to this resistance, backing us into a corner when treating infections caused by these and other types of bacteria. Unfortunately, we have taken our first steps into a post-antibiotic era. This makes the use of vaccines all the more important.
Reviewed by Paul A. Offit, MD, Lori Handy, MD, MSCE on March 02, 2017