Invasive Pneumococcal Disease Among Immunocompromised Persons: Implications for Vaccination Programs.
BACKGROUND
In 2012/2013, a single dose of 13-valent pneumococcal conjugate vaccine (PCV13) was recommended for immunocompromised adults in the United States and Canada. To assess the potential benefits of this recommendation, we assessed the serotype-specific burden of invasive pneumococcal disease (IPD) among immunocompromised individuals.


METHODS
From 1995 to 2012, population-based surveillance for IPD was conducted in Metropolitan Toronto and Peel Region, Canada. Disease incidence and case fatality were measured in immunocompromised populations over time, and the contribution of different serotypes determined.


RESULTS
Overall, 2115/7604 (28%) episodes of IPD occurred in immunocompromised persons. IPD incidence was 12-fold higher (95% confidence interval [CI], 8.7-15) in immunocompromised compared to immunocompetent persons; the case fatality rate was elevated in both younger (odds ratio [OR] 1.8) and older (OR 1.3) adults. Use of immunosuppressive medications was associated with a 2.1-2.7 fold increase in the risk of IPD. Five years after PPV23 program implementation, IPD incidence had declined significantly in immunocompromised adults (IRR 0.57, 95% CI, .40-.82). Ten years after pediatric PCV7 authorization, IPD due to PCV7 serotypes had decreased by 90% (95% CI, 77%-96%) in immunocompromised persons of all ages. In 2011/2012, 37% of isolates causing IPD in immunocompromised persons were PCV13 serotypes and 27% were PPV23/not PCV13 serotypes.


CONCLUSIONS
Immunocompromised individuals comprised 28% of IPD. Both PPV23 and herd immunity from pediatric PCV7 were associated with reductions in IPD in immunocompromised populations. PCV13 vaccination of immunocompromised adults may substantially reduce the residual burden until herd immunity from pediatric PCV13 is fully established.
Mount Sinai Hospital.
Altynay
A
Shigayeva
Mount Sinai Hospital University of Toronto.
Wallis
W
Rudnick
Mount Sinai Hospital.
Karen
K
Green
Mackenzie Health, Richmond Hill Southlake Regional Health Centre, Newmarket.
Danny K
DK
Chen
National Microbiology Laboratory, Winnipeg.
Walter
W
Demczuk
University of Toronto University Health Network.
Wayne L
WL
Gold
St. Joseph's Health Centre.
Jennie
J
Johnstone
University of Toronto Rouge Valley Health System.
Ian
I
Kitai
University of Toronto St. Joseph's Health Centre.
Sigmund
S
Krajden
The Scarborough Hospital.
Reena
R
Lovinsky
University of Toronto St. Michael's Hospital.
Matthew
M
Muller
Toronto East General Hospital.
Jeff
J
Powis
University of Toronto Halton Healthcare Services, Oakville.
Neil
N
Rau
University of Toronto University Health Network.
Sharon
S
Walmsley
Alberta Provincial Public Health Laboratory, Edmonton.
Gregory
G
Tyrrell
University of Toronto The Hospital for Sick Children, Toronto, Canada.
Ari
A
Bitnun
Mount Sinai Hospital University of Toronto.
Allison
A
McGeer
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D032521:Immunity, Herd; D016867:Immunocompromised Host; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D065288:Serogroup; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000302:isolation & purification*; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
C538862:13-valent pneumococcal vaccine; D022242:Pneumococcal Vaccines
IPD; immunocompromised; pneumococcal vaccine