Abstract
Background: The 13-valent pneumococcal conjugate vaccine (PCV13) was recently shown to be effective against PCV13-type invasive pneumococcal disease (IPD) and pneumococcal community acquired pneumonia (CAPSpn) in healthy adults aged ≥65 years, prompting many countries to re-assess adult immunization. In Canada, the potential benefits of adult PCV13 immunization were unclear given anticipated herd immunity from PCV13 childhood immunization introduced since 2010. This study describes the serotype distribution and clinical outcomes of Canadian adults aged ≥16 years, who were hospitalized with CAPSpn and IPD from 2010 to 2015. Methods: Active surveillance for CAP and IPD was performed in adult hospitals across five Canadian provinces. IPD was identified when Streptococcus pneumoniae was isolated from sterile sites. Bacteremic and non-bacteremic CAPSpn were identified using blood culture, and sputum culture or PCV13-specific urine antigen detection (UADPCV13), respectively. Serotype was assigned using Quellung reaction, PCR, or UADPCV13. Results: Of 6687 CAP cases where a test was performed, S. pneumoniae positivity decreased from 15.9% in 2011 to 8.8% in 2014, but increased to 12.9% in 2015. CAPSpn attributed to PCV13 serotypes followed a similar trend, dropping from 8.3% in 2010 to 4.6% in 2014, but increasing to 6.3% in 2015. The decline was primarily attributed to serotypes 7F and 19A, and the proportional increase to serotype 3. Similar trends were noted for bacteremic and non-bacteremic CAPSpn. Serious outcomes such as 30-day mortality, intensive care unit admission, and requirement for mechanical ventilation were prominent in CAPSpn and IPD cases, but remained unchanged over the study years. Conclusion: Herd immunity afforded primarily by serotypes 7F and 19A appears to be partly masked by a concomitant proportional increase of serotype 3. Despite evidence of herd immunity, these PCV13 serotypes remain persistent in Canadian adults hospitalized with CAPSpn, and represent between 5 and 10% of all CAP in this patient population.
| Original language | English |
|---|---|
| Pages (from-to) | 5466-5473 |
| Number of pages | 8 |
| Journal | Vaccine |
| Volume | 37 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - Aug 23 2019 |
Bibliographical note
Funding Information:SAM received research grants from GlaxoSmithKline, Pfizer, Sanofi Pasteur; LV received research grants from GlaxoSmithKline, Pfizer, Optimer, Cubist and Merck, and personal fees from Merck, Optimer and Cubist. No other conflicts were declared.
Funding Information:
This work was supported by the Public Health Agency of Canada (PHAC), the Canadian Institutes of Health Research (CIHR), and by an investigator-initiated research grant to CIRN from Pfizer Canada. No study sponsors were involved in study design, specimen collection, analysis and interpretation of data, scientific writing, or decision to submit the paper for publication. The grant identification numbers associated with the funding were CIHR 23338, GSK1106, and PF1001.
Funding Information:
The authors would like to thank all CIRN SOS surveillance monitors and staff at the Canadian Center for Vaccinology (CCfV) who were instrumental in the recruitment, collection, and processing of CAP and IPD specimens. Also, the technical assistance of the laboratory staff at the Streptococcus and Sexual Transmitted Diseases unit of the National Microbiology Laboratory (NML), Public Health Agency of Canada (PHAC), was greatly appreciated.
Publisher Copyright:
© 2019 The Authors
ASJC Scopus Subject Areas
- Molecular Medicine
- General Immunology and Microbiology
- General Veterinary
- Public Health, Environmental and Occupational Health
- Infectious Diseases
