MedicalResearch: What is the background for this study?
Dr. Moore: Since introduction, pneumococcal conjugate vaccines have resulted in dramatic decreases in the number of cases of invasive pneumococcal disease in both children and adults. The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced into the routine infant immunization program in the United States in 2000. It was recommended for infants using a 4-dose schedule: 2, 4, 6, and 12 through 15 months of age. Studies showed that PCV7 was highly effective in preventing invasive pneumococcal disease. In 2010, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 using the same 4-dose schedule. PCV13 is similar to PCV7, but includes protection against six additional serotypes of Streptococcus pneumoniae. There are more than 90 serotypes of pneumococcal bacteria.
Streptococcus pneumoniae, or pneumococcus, is a major cause of illness and death globally. Pneumococcus can cause many types of illness that ranging from mild to life-threatening, including pneumonia, ear and sinus infections, meningitis, and bacteremia. Some of these infections are considered invasive because they invade parts of the body that are normally free from bacteria. Invasive pneumococcal disease, including meningitis and bacteremia, is often severe and can be deadly.
MedicalResearch: What are the main findings?
Dr. Moore: Invasive pneumococcal disease decreased substantially in the first 3 years after PCV13 was introduced into the U.S. infant immunization schedule. By June 2013, more than 30,000 cases of invasive pneumococcal disease and 3,000 deaths are estimated to have been prevented in the United States due to PCV13. Children under the age of five, which is the age group that actually received the vaccine, experienced the greatest and quickest benefit from PCV13. For example, the overall number of cases of invasive pneumococcal disease decreased by 64% in this age group between 2010 and 2013. Significant decreases were seen as early as six months after the immunization recommendation was made.
Adults, who were not targeted for vaccination, also experienced health benefits from PCV13 introduction. For example, the overall number of cases of invasive pneumococcal disease decreased by 32% for adults aged 18 to 49 years, while adults 65 and older experienced a more modest 12% decrease. These reductions are further evidence that both PCV7 and PCV13 reduce the spread of pneumococcus, which is why vaccinating children leads to disease reductions in adults.
For both children and adults, the greatest reductions were seen in the number of cases of invasive pneumococcal disease that were caused by serotypes that are covered by PCV13 but not PCV7 (serotypes 19A and 7F specifically).
MedicalResearch: What should clinicians and patients take away from your report?
Dr. Moore: Pneumococcal conjugate vaccines are highly effective in preventing severe illnesses caused by pneumococcus. All children should get four doses of PCV13 for best protection.
Since 2012, CDC’s Advisory Committee on Immunization Practices has expanded PCV13 recommendations to three new groups:
- Children 6 through 18 years of age with certain medical conditions should receive a dose of PCV13 if they have not previously received a dose. (These medical conditions include sickle cell disease, HIV-infection, or other immunocompromising conditions; cochlear implant; or cerebrospinal fluid (CSF) leaks.)
- Adults 19 years and older with immunocompromising conditions should also receive a dose of PCV13.
- All adults 65 years and older should receive one dose of PCV13 in series with the 23-valent pneumococcal polysaccharide vaccine – PPSV23. (For best protection, PCV13 should be given first whenever possible, followed 6 to 12 months later by PPSV23.)
MedicalResearch: What recommendations do you have for future research as a result of this study?
Dr. Moore: Serotype replacement has been documented since the introduction of PCV7. This means that invasive pneumococcal disease caused by serotypes not covered by PCV7 increased modestly since 2000. This study noted some evidence of serotype replacement since the introduction of PCV13, but only among adults 50 to 64 years of age and only during the third year. Early evidence of serotype replacement seems to be emerging in Europe and further research is needed to see if it becomes widespread in the United States.
Matthew R Moore, Ruth Link-Gelles, William Schaffner, Ruth Lynfield, Catherine Lexau, Nancy M Bennett, Susan Petit, Shelley M Zansky, Lee H Harrison, Arthur Reingold, Lisa Miller, Karen Scherzinger, Ann Thomas, Monica M Farley, Elizabeth R Zell, Thomas H Taylor Jr, Tracy Pondo, Loren Rodgers, Lesley McGee, Bernard Beall, James H Jorgensen, et al. Lesley McGee, PhD
Bernard Beall, PhD Prof James H Jorgensen, PhD Cynthia G Whitney, MDa The Lance
MedicalResearch.com Interview with:, & Dr Matthew R Moore, MD (2015). Pneumococcal Vaccines Prove Highly Effective In Preventing Severe Illness MedicalResearch.com