Vaccine-Type Pneumococcal Disease (IPD) and Patterns of Penicillin and Cefotaxime Non-Susceptibility Following Routine Use of 13-Valent Conjugate Pneumococcal Infant Vaccination in the United States

Background: The use of PCV13 in the US routine infant pneumococcal vaccination program started in February 2010 as a replacement of PCV7, in use since 2000. The use of PCVs in children has reduced the incidence of IPD and other pneumococcal diseases not only in children but also across all-age groups. Antibiotic resistance to pneumococcal bacteria has been observed. We compared trends of IPD cumulative incidence with trends of antibiotic resistance to penicillin and cefotaxime in IPD isolates. Both antibiotic classes are commonly used to treat IPD.

 

Methods: Annual IPD-cases/100,000 population and percentage of antibiotic non-susceptible isolates for 2009-2013 were assessed. Data sources consisted of publications from the U.S. Active Bacterial Core surveillance for Streptococcus pneumoniae.

Results: In the US, in the years following the introduction of PCV13, vaccine-type IPD incidence decreased from 7.4 to 3.3 cases per 100,000 population from 2009 through 2013. Similarly, serotype-19A IPD incidence also decreased from 2.3 to 0.6 per 100,000 population. The percentage of penicillin and cefotaxime’s non-susceptible IPD isolates also decreased monotonically over time from 10.6% and 8.6% in 2010 to 4.7% and 2.6% in 2013, respectively.  There were strong and positive linear correlations between vaccine-type IPD and serotype-19A IPD with penicillin and cefotaxime’s non-susceptibility (r=0.982 and 0.939 for vaccine-type IPD; r=0.986 and r=0.950 for serotype-19A IPD).

Conclusion: PCV13 implementation and its impact on vaccine-type IPD is associated with the observed reductions in penicillin and cephalosporin’s non-susceptibility in IPD. Serotype-19A, a serotype commonly associated with antibiotic resistance has declined with PCV13 use. There are important public health implications to be further analyzed.