Respiratory infection and otitis media visits in relation to pneumococcal conjugate vaccine use in Saskatchewan.
BACKGROUND
In Saskatchewan, pneumococcal conjugate vaccination (PCV) was offered to high-risk children in 2002 and to all infants in 2005.


OBJECTIVE
To describe trends in the frequency of medical visits for lower respiratory tract infection (LRI) and otitis media (OM) in relation to PCV use during the period 1990 to 2008.


METHODS
Statistics regarding the number of children covered by the health insurance plan, PCV administration, and medical visits with a diagnostic code associated with LRI and OM were provided by Saskatchewan Health. Monthly rates were analyzed using dynamic state space models.


RESULTS
In all series, there was a marked seasonal cycle and some higher-than-expected winter peak values, possibly associated with epidemics of specific respiratory viruses. Three abrupt decreases in baseline rate were observed for LRI and the final one, in February 2007, could be related to the increased proportion of children vaccinated with PCV. There was no statistical correlation between PCV use and OM visit frequency.


CONCLUSIONS
Many environmental, biological and administrative factors may influence health services use, and an effect of low magnitude of a particular vaccine pertaining to nonspecific outcomes could be obscured in time-series analyses.
Quebec National Public Health Institute, Quebec City, Quebec;
Ngoc-Hang
NH
Khuc
Department of Pediatrics, University of Saskatchewan, Saskatoon;
Ben
B
Tan
Population Health Branch, Ministry of Health, Regina, Saskatchewan;
Rosalie
R
Tuchscherer
GlaxoSmithKline, Mississauga (currently Eastlake Research Group, Oakville), Ontario;
Nigel Sb
NS
Rawson
Quebec National Public Health Institute, Quebec City, Quebec; ; Department of Social and Preventive Medicine, Laval University; ; Quebec University Hospital Research Centre, Quebec City, Quebec.
Philippe
P
De Wals
Otitis media; Pneumococcal conjugate vaccine; Pneumonia; Program evaluation