Pneumococcal vaccine
The pneumococcal vaccine is designed to protect against diseases caused by various strains of the Streptococcus pneumoniae bacteria, which can lead to serious health conditions such as pneumonia, middle-ear infections, sinusitis, bacteremia, and meningitis. The vaccine works by using the polysaccharide coating of the bacteria linked to a protein, stimulating the body's immune response without causing the disease. There are different formulations of the vaccine, including the Prevnar 20, which covers twenty of the most dangerous types for children, and Pneumovax, which targets the twenty-three most common types in adults.
Since its introduction in 1977, the pneumococcal vaccine has evolved significantly, with updates improving its effectiveness and coverage over the years. Children are recommended to receive the 20-valent vaccine at specific ages, while older adults and those at higher risk receive the 23-valent version. The vaccine has played a crucial role in reducing antibiotic resistance associated with pneumococcal diseases and has had a substantial positive impact on public health by decreasing instances of severe infections among vaccinated populations. Additionally, vaccination contributes to herd immunity, protecting vulnerable individuals who cannot be vaccinated.
Pneumococcal vaccine
- ALSO KNOWN AS: Pneumococcal polysaccharide vaccine, Streptococcus pneumoniae vaccine
Definition
The pneumococcal vaccine prevents disease caused by various types of Streptococcus pneumoniae bacteria (also known as pneumococcus), depending on the type of immunization administered. These diseases include pneumonia, middle-ear infection (otitis media), and sinusitis. Pneumococcal disease can spread quickly to the blood and spinal cord, resulting in bacteremia and meningitis, respectively, the effects of which can be devastating.
Mechanism of Action
The vaccine is made by taking the shell, or polysaccharide coating, of the S. pneumoniae bacterium and linking it to another protein. Injection of this safe combination incites the body to produce an immune response against this bacterial coating without causing the disease, thus protecting against future infection.
Eighty-five different types of S. pneumoniae bacteria exist. The polysaccharide coatings from the thirteen types that are most dangerous to children are those found in the Prevnar 13 vaccine. The Prevnar 20 vaccine, the newest iteration recommended for children, covers twenty types. The coatings from the twenty-three most commonly encountered types of S. pneumoniae are used for the adult version of the vaccine, Pneumovax.
Vaccine History
The first pneumococcal vaccine was licensed in 1977 and protected against fourteen types of S. pneumoniae. The most recent 23-valent form of the vaccine was released in 1983 under the name Pneumovax. In 2000, the 7-valent pediatric form of the pneumococcal vaccine was licensed under the name Prevnar, and routine administration to all children was recommended. The pediatric vaccine was further improved to provide broader coverage against pneumococcal disease with the 13-valent form of Prevnar released in 2010. Prevnar 20 was approved for use in adults in 2021 and children in 2023.
Administration
Medical experts recommend that children receive the 20-valent pneumococcal vaccine at two, four, six, and twelve to fifteen months of age. The 23-valent pneumococcal vaccine is given as a separate immunization to all adults aged sixty-five years and older and children aged two years and older at high risk of developing pneumococcal disease. Routine administration in adults between these age groups is also recommended if the person smokes cigarettes or has asthma.
Impact
Before the development of the pneumococcal vaccine, diseases caused by pneumococcus were rapidly becoming resistant to the antibiotics available, rendering them more virulent and difficult to treat. The introduction of the pneumococcal vaccine helped prevent these diseases, making antibiotic resistance less of an issue. However, these bacteria continue to be resistant, making prevention the primary focus of public health efforts. Still, the pneumococcal vaccine has significantly impacted public health for children and adults, reducing the impacts of diseases such as pneumonia, meningitis, and bacteremia. Further, widespread vaccination with the pneumococcal vaccine protects the vaccinated and provides herd immunity for those too young to receive vaccinations or whose immune systems are compromised.
Bibliography
Behrman, Richard E., et al., editors. Nelson Textbook of Pediatrics. 20th ed., Elsevier, 2016. 2 vols.
Fisher, Margaret C. Immunizations and Infectious Diseases: An Informed Parent’s Guide. American Academy of Pediatrics, 2006.
Harvey, Richard A., et al. Lippincott’s Illustrated Reviews: Microbiology. 3rd ed., Lippincott Williams and Wilkins, 2013.
Loehr, Jamie. The Vaccine Answer Book: Two Hundred Essential Answers to Help You Make the Right Decisions for Your Child. Sourcebooks, 2010.
Plotkin, Stanley A., et al. Vaccines. 6th ed., Philadelphia: Elsevier, 2013.
"Pneumococcal Polysaccharide Vaccine." MedlinePlus, National Library of Medicine, 15 Mar. 2020, medlineplus.gov/druginfo/meds/a607022.html. Accessed 6 Oct. 2024.
"Pneumococcal Vaccination." CDC, 12 Sept. 2024, www.cdc.gov/pneumococcal/vaccines/index.html. Accessed 6 Oct. 2024.
Streeter, Adam J., et al. "Real-world Effectiveness of Pneumococcal Vaccination in Older Adults: Cohort Study Using the UK Clinical Practice Research Datalink." PLoS ONE, vol. 17, no. 10, 2022, doi.org/10.1371/journal.pone.0275642. Accessed 6 Oct. 2024.
"U.S. FDA Approves PREVNAR 20®, Pfizer's 20-valent Pneumococcal Conjugate Vaccine for Infants and Children." Pfizer, 27 Apr. 2023, www.pfizer.com/news/press-release/press-release-detail/us-fda-approves-prevnar-20r-pfizers-20-valent-pneumococcal. Accessed 6 Oct. 2024.