Impact of 13-Valent Pneumococcal Conjugate Vaccine (PCV13) Use on Invasive Pneumococcal Disease (IPD) Among Adults With Chronic Conditions, United States

Abstract

Background. PCV13 introduction among US children in 2010 reduced IPD among adults through reduced transmission. In 2012, PCV13 was recommended for adults ≥19 years old with immunocompromising conditions in series with 23-valent polysaccharide vaccine (PPSV23). We evaluated direct and indirect effects of PCV13 on IPD among adults with selected chronic conditions, such as hematologic malignancies and solid cancer (indications for PCV13 and PPSV23) or chronic heart, lung, or liver disease, diabetes, alcoholism, and smoking (indications for PPSV23 alone). Methods. IPD cases were defined as isolation of pneumococcus from sterile sites in residents of Active Bacterial Core surveillance (ABCs) sites 19-64 years of age during 2007-2014. Chart reviews ascertained presence of conditions. Isolates serotyped by Quellung were classified as PCV13, PPSV11 (unique to PPSV23), or non-vaccine type (NVT). Percent changes in IPD incidence between pre-PCV13 (2007-2008) and post- PCV13 (2013-2014) periods and 95% confidence intervals (95% CI) were estimated. Rate ratios (RR) compared incidence among adults with vaccine indications to healthy during pre- and post-PCV13 period. Results. Of 15,305 IPD cases aged 19-64 years identified during 2007-2014, 4931 were in those with PCV13 indications; 9862 had indications for PPSV23 only. Overall and PCV13-type IPD rates declined significantly for all groups. Reductions in PCV13- type IPD were 57% (95% CI -68 to -43) and 59% (95% CI -63 to -53) for adults with and without PCV13 indications, respectively. PPSV11-type IPD increased for those with PPSV23 only indications (percent change: 29%; 95% CI 17 to 44). No changes were observed in NVT IPD for all groups. Incidence among adults with vaccine indications was 2-6 times higher than among healthy adults (figure). Conclusion. Findings suggest that PCV13 introduction in the U.S. reduced IPD incidence among adults 19-64 years old, although adults with chronic conditions continue to experience higher IPD rates compared to healthy adults in the post-PCV13 period. The similar reductions among those with and without PCV13 indications and the remaining vaccine preventable disease burden among those with PCV13 indications suggest that observed benefits are largely due to indirect PCV13 effects.