Age-related trends in the timeliness and prediction of medical visits, hospitalizations and deaths due to pneumonia and influenza, British Columbia, Canada, 1998-2004.
The influenza immunization program in North America has been primarily designed to provide direct benefit to vaccinated individuals at highest risk of serious influenza outcomes. Some evidence suggests that immunization of certain age groups may also extend indirect protective benefit to vulnerable populations. Our goal was to identify age groups associated earliest with seasonal influenza activity and who may have the greatest indirect impact at the population level. We examined age-based associations between influenza medical visits and population-wide hospitalization/mortality due to pneumonia & influenza (P&I) using administrative datasets in British Columbia, Canada. A peak week was identified for each age group based on the highest rates observed in a given week for that study year. Mean rates at the peak week were averaged over the study years per age group. Timeliness (T) was defined as the mean difference in days between the first peak in influenza medical visits and population-wide P&I hospitalizations/deaths. Poisson regression was applied to calculate prediction (Pr) as the average proportion of deviance in P&I explained by influenza medical visits. T and Pr were derived by age group, and the product (T x Pr) was used as a summary measure to rank potential indirect effects of influenza by age group. Young children (0-23 months) and the elderly (> or = 65 years) had the highest peak rates of P&I hospitalization. Children
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Cites: N Engl J Med. 2000 Jan 27;342(4):225-3110648763
Cites: J Infect Dis. 1998 Jul;178(1):53-609652423
Cites: JAMA. 2000 Oct 4;284(13):1677-8211015798
Cites: N Engl J Med. 2001 Mar 22;344(12):889-9611259722
Cites: JAMA. 2003 Jan 8;289(2):179-8612517228
Cites: JAMA. 2003 May 21;289(19):2500; author reply 2500-212759318
Cites: MMWR Recomm Rep. 2004 May 28;53(RR-6):1-4015163927
Cites: Can Commun Dis Rep. 2004 Jun 15;30:1-3215239483
Cites: JAMA. 2004 Sep 15;292(11):1333-4015367555
Cites: J Infect Dis. 2004 Oct 15;190(8):1369-7315378427
Cites: Bull World Health Organ. 1969;41(3):537-425309469
Cites: Pediatrics. 1999 Jun;103(6):e7310353970
Cites: CMAJ. 2004 Nov 9;171(10):1213-2215534315
Cites: Vaccine. 2005 Feb 18;23(13):1540-815694506
Cites: Am J Epidemiol. 2005 Oct 1;162(7):686-9316107568
Cites: JAMA. 2005 Dec 7;294(21):2712-916333006
Cites: N Engl J Med. 2005 Dec 15;353(24):2559-6716354892