Fast Five Quiz: Pneumococcal Infections

Jocelyn Y. Ang, MD


September 15, 2021

Pneumococcal bacteria are resistant to one or more antibiotics in 3 out of every 10 cases. The number of antibiotic-resistant pneumococcal infections has decreased due to the success of the pneumococcal conjugate vaccine. In addition to the vaccine, appropriate use of antibiotics may also slow or reverse drug-resistant pneumococcal infections.

The pneumococcal conjugate vaccine helps to prevent infections, and it slows the development of pneumococcal resistance. It has reduced pneumococcal infections caused by vaccine strains, most of which were resistant, by more than 90% in children. It has also decreased the spread of resistant S pneumoniae strains (because vaccinated people do not spread the bacteria). Blocking the spread reduces resistant infections among children, as well as adults, through vaccine indirect effects ("herd immunity").

From 2000 to 2009, seven-valent pneumococcal conjugate vaccine (PCV7) provided protection against seven pneumococcal strains. These strains caused more than 83% of the antibiotic-resistant invasive infections in children before the introduction of PCV7. Starting in 2010, the use of PCV13 expanded that protection to 13 strains; serotype 19A accounted for more than 30% of resistant infections before the introduction of PCV13.

Since the introduction of PCV in 2000, the rates of antibiotic-resistant invasive pneumococcal infections caused by vaccine strains decreased by 97% among children younger than 5 years and by more than 60% among adults. These findings show that achieving high vaccination coverage and encouraging appropriate antibiotic use will slow the spread of pneumococcal resistance.

Learn more about pneumococcal resistance.


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