Figure 1.
Pneumonia and influenza (P&I) mortality rates among the Japanese (A) and US (B) elderly, aged 65–89 years, Jan. 1977–Dec. 2006.
Expected mortality rates in the absence of influenza virus circulation are shown in black, as determined by the Serfling seasonal baseline approach. Influenza epidemic months are highlighted in grey.
Figure 2.
Seasonal excess pneumonia and influenza (P&I) mortality rates among the Japanese (A) and the US elderly (B), aged 65–89 years, 1977–78 to 2005–06 seasons.
Squares represent seasons dominated by influenza A/H3N2 viruses; circles represent seasons dominated by influenza A/H1N1 or B. Blue symbols represent crude excess mortality estimates; red symbols represent excess mortality estimates adjusted for population aging and trends in baseline mortality risk. The blue and red lines represent 5-yr moving averages of the crude and adjusted seasonal excess mortality rates, respectively. Grey bars in (A) represent the number of vaccine doses distributed per influenza season in Japan; grey bars in (B) represent the influenza vaccine coverage among the US non-institutionalized elderly aged ≥65.
Figure 3.
Crude (left panels) and adjusted (right panels) excess pneumonia & influenza (P&I) seasonal mortality rates by age group and time period in Japan (top) and the US (bottom).
Rates were adjusted for time trends in the baseline risk of mortality. Asterisks indicate statistically significant differences between the two time periods using Wilcoxon's Rank Sum Test (P<0.05).
Table 1.
Average excess P&I mortality rates per 100,000 in Japanese and US seniors aged 65–89 yrs, 1978–2006.
Table 2.
Relative risks of excess P&I death among seniors aged 65–89 in 1995–2006 compared to 1978–1994 in Japan and the US, controlling for influenza subtype dominance, population aging, and trends in baseline risk of mortality.