The number of pneumococcal serotypes with high potential for causing invasive disease decreased in France after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13), according to a study published in Vaccine by Dr. Emmanuelle Varon of the Hospital Européen Georges Pompidou in Paris and her colleagues.
Only two nonvaccine serotypes, 24F and 12F, had a high invasive disease potential in children under the age of 2 years after PCV13 was made available in 2010, researchers found. This is a decrease from five serotypes – 7F, 3, 1, 24F and 19A – previously known to have had a high invasive disease potential, when children were offered a seven-valent vaccine (PCV7).
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During two study periods, 2008-2009 (before PCV13) and 2012-2013 (after PCV13), researchers looked at 355 pneumococci isolated from 1,212 healthy children aged 6-24 months and from 569 children with invasive pneumococcal disease (IPD), including 166 with meningitis, 114 with pneumonia, and 289 with other IPDs. During the second study period, the number of pneumococcal isolates was reduced for overall IPD (53%), meningitis (37%), pneumonia (66%), and other IPDs (56%). PCV7 serotypes almost disappeared between the two time frames.
Ongoing surveys are needed “to further characterize the little-known [nonvaccine serotypes], which are still poorly represented,” the authors wrote.
Read the article in Vaccine (doi: 10.1016/j.vaccine.2015.10.015).