Limits...
All-cause mortality during first wave of pandemic (H1N1) 2009, New South Wales, Australia, 2009.

Muscatello DJ, Cretikos MA, Macintyre CR - Emerging Infect. Dis. (2010)

Bottom Line: Differentiating observed death rates from the seasonally oscillating baseline provides estimated influenza-associated death rates.Total differences between weekly observed and baseline rates during May-September provided annual estimates of influenza-associated death rates.This estimate is consistent with a pandemic virus causing mild illness in most persons infected and sparing older persons.

View Article: PubMed Central - PubMed

Affiliation: New South Wales Department of Health, North Sydney, New South Wales, Australia. dmusc@doh.health.nsw.gov.au

ABSTRACT
In temperate countries, death rates increase in winter, but influenza epidemics often cause greater increases. The death rate time series that occurs without epidemic influenza can be called a seasonal baseline. Differentiating observed death rates from the seasonally oscillating baseline provides estimated influenza-associated death rates. During 2003-2009 in New South Wales, Australia, we used a Serfling approach with robust regression to estimate age-specific weekly baseline all-cause death rates. Total differences between weekly observed and baseline rates during May-September provided annual estimates of influenza-associated death rates. In 2009, which included our first wave of pandemic (H1N1) 2009, the all-age death rate was 6.0 (95% confidence interval 3.1-8.9) per 100,000 persons lower than baseline. In persons ?80 years of age, it was 131.6 (95% confidence interval 126.2-137.1) per 100,000 lower. This estimate is consistent with a pandemic virus causing mild illness in most persons infected and sparing older persons.

Show MeSH

Related in: MedlinePlus

Weekly age-specific all-cause death rates per 100,000 population (black), fitted seasonal baseline (green), weekly pneumonia and influenza deaths (P&I) per 250,000 population (blue), and all-age weekly proportion of respiratory samples positive for influenza, New South Wales, Australia, January 2003–September 2009. The weekly proportion of respiratory samples positive for influenza was drawn from data provided by up to 8 major New South Wales public pathology laboratories for persons of all ages. Testing was by direct immunofluorescence or PCR. These data were reported only during May–September each year.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3294965&req=5

FA.1: Weekly age-specific all-cause death rates per 100,000 population (black), fitted seasonal baseline (green), weekly pneumonia and influenza deaths (P&I) per 250,000 population (blue), and all-age weekly proportion of respiratory samples positive for influenza, New South Wales, Australia, January 2003–September 2009. The weekly proportion of respiratory samples positive for influenza was drawn from data provided by up to 8 major New South Wales public pathology laboratories for persons of all ages. Testing was by direct immunofluorescence or PCR. These data were reported only during May–September each year.

Mentions: The seasonal fluctuations in mortality were more evident in the older age groups, and death rates in persons 65–79 years of age also declined steadily over the study period (Figure A1). Among persons >80 years of age, periods of increased death rates in the cooler months relative to baseline occurred in 2003, 2004, 2007, and 2008. These correspond to increases in P&I deaths and influenza circulation. Among persons 65–79 years of age, sustained peaks above baseline that correspond to influenza activity and peaks in P&I deaths are evident in 2003, 2007, and 2008. Among persons aged 50–64 years, a clear and consistent peak is evident in 2007, and possibly in 2009. Among persons 20–49 years of age, a peak is evident only in 2007, although the time series in that age group varied substantially. Among persons 0–19 years of age, no peaks clearly coincide with influenza activity. An increase coinciding with influenza circulation can be discerned in 2003, and a short-lived peak is evident in 2009, but some similar and larger peaks occurred at various times during the 7 years, not always when influenza was circulating (Figure A1).


All-cause mortality during first wave of pandemic (H1N1) 2009, New South Wales, Australia, 2009.

Muscatello DJ, Cretikos MA, Macintyre CR - Emerging Infect. Dis. (2010)

Weekly age-specific all-cause death rates per 100,000 population (black), fitted seasonal baseline (green), weekly pneumonia and influenza deaths (P&I) per 250,000 population (blue), and all-age weekly proportion of respiratory samples positive for influenza, New South Wales, Australia, January 2003–September 2009. The weekly proportion of respiratory samples positive for influenza was drawn from data provided by up to 8 major New South Wales public pathology laboratories for persons of all ages. Testing was by direct immunofluorescence or PCR. These data were reported only during May–September each year.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3294965&req=5

FA.1: Weekly age-specific all-cause death rates per 100,000 population (black), fitted seasonal baseline (green), weekly pneumonia and influenza deaths (P&I) per 250,000 population (blue), and all-age weekly proportion of respiratory samples positive for influenza, New South Wales, Australia, January 2003–September 2009. The weekly proportion of respiratory samples positive for influenza was drawn from data provided by up to 8 major New South Wales public pathology laboratories for persons of all ages. Testing was by direct immunofluorescence or PCR. These data were reported only during May–September each year.
Mentions: The seasonal fluctuations in mortality were more evident in the older age groups, and death rates in persons 65–79 years of age also declined steadily over the study period (Figure A1). Among persons >80 years of age, periods of increased death rates in the cooler months relative to baseline occurred in 2003, 2004, 2007, and 2008. These correspond to increases in P&I deaths and influenza circulation. Among persons 65–79 years of age, sustained peaks above baseline that correspond to influenza activity and peaks in P&I deaths are evident in 2003, 2007, and 2008. Among persons aged 50–64 years, a clear and consistent peak is evident in 2007, and possibly in 2009. Among persons 20–49 years of age, a peak is evident only in 2007, although the time series in that age group varied substantially. Among persons 0–19 years of age, no peaks clearly coincide with influenza activity. An increase coinciding with influenza circulation can be discerned in 2003, and a short-lived peak is evident in 2009, but some similar and larger peaks occurred at various times during the 7 years, not always when influenza was circulating (Figure A1).

Bottom Line: Differentiating observed death rates from the seasonally oscillating baseline provides estimated influenza-associated death rates.Total differences between weekly observed and baseline rates during May-September provided annual estimates of influenza-associated death rates.This estimate is consistent with a pandemic virus causing mild illness in most persons infected and sparing older persons.

View Article: PubMed Central - PubMed

Affiliation: New South Wales Department of Health, North Sydney, New South Wales, Australia. dmusc@doh.health.nsw.gov.au

ABSTRACT
In temperate countries, death rates increase in winter, but influenza epidemics often cause greater increases. The death rate time series that occurs without epidemic influenza can be called a seasonal baseline. Differentiating observed death rates from the seasonally oscillating baseline provides estimated influenza-associated death rates. During 2003-2009 in New South Wales, Australia, we used a Serfling approach with robust regression to estimate age-specific weekly baseline all-cause death rates. Total differences between weekly observed and baseline rates during May-September provided annual estimates of influenza-associated death rates. In 2009, which included our first wave of pandemic (H1N1) 2009, the all-age death rate was 6.0 (95% confidence interval 3.1-8.9) per 100,000 persons lower than baseline. In persons ?80 years of age, it was 131.6 (95% confidence interval 126.2-137.1) per 100,000 lower. This estimate is consistent with a pandemic virus causing mild illness in most persons infected and sparing older persons.

Show MeSH
Related in: MedlinePlus