Despite concern about the rise of nonvaccine serotypes following widespread PCV13 immunization, cases of community-acquired pneumonia (CAP) remain nearly as low as after initial implementation of the vaccine and severe cases have not risen at all.
This was the finding of a prospective time-series analysis study from eight French pediatric emergency departments between June 2009 and May 2017.
The 12,587 children with CAP enrolled in the study between June 2009 and May 2017 were all aged 15 years or younger and came from one of eight French pediatric EDs.
Pediatric pneumonia cases per 1,000 ED visits dropped 44% after PCV13 was implemented, a decrease from 6.3 to 3.5 cases of CAP per 1,000 pediatric visits from June 2011 to May 2014, with a slight but statistically significant increase to 3.8 cases of CAP per 1,000 pediatric visits from June 2014 to May 2017. However, there was no statistically significant increase in cases with pleural effusion, hospitalization, or high inflammatory biomarkers.
“These results contrast with the recent increase in frequency of invasive pneumococcal disease observed in several countries during the same period linked to serotype replacement beyond 5 years after PCV13 implementation,” reported Naïm Ouldali, MD, of the Association Clinique et Thérapeutique Infantile du Val-de-Marne in France, and associates. The report is in.
“This difference in the trends suggests different consequences of serotype replacement on pneumococcal CAP vs invasive pneumococcal disease,” they wrote. “The recent slight increase in the number of all CAP cases and virus involvement may reflect changes in the epidemiology of other pathogens and/or serotype replacement with less pathogenic serotypes.”
This latter point arose from discovering no dominant serotype during the study period. Of the 11 serotypes not covered by PCV13, none appeared in more than four cases.
“The implementation of PCV13 has led to the quasi-disappearance of the more invasive serotypes and increase in others in nasopharyngeal flora, which greatly reduces the frequency of the more severe forms of CAP, but could also play a role in the slight increase in frequency of the more benign forms,” the authors reported.
Among the study’s limitations was lack of a control group, precluding the ability to attribute findings to any changes in case reporting. And “participating physicians were encouraged to not change their practice, including test use, and no other potential interfering intervention.”
Funding sources for this study included the Pediatric Infectious Diseases Group of the French Pediatrics Society, Association Clinique et Thérapeutique Infantile du Val-de-Marne, the Foundation for Medical Research and a Pfizer Investigator Initiated Research grant.
Dr Ouldali has received grants from GlaxoSmithKline, and many of the authors have financial ties and/or have received non-financial support from AstraZeneca, Biocodex, GlaxoSmithKline, Merck, Novartis, Pfizer and/or Sanofi Pasteur.
SOURCE: Ouldali N et al. JAMA Pediatrics. 2019 Feb 4. doi: .