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.

Model Outcome	Adjusted RR (1978–1994 v. 1995–2006)	Adjusted Protective Effectiveness of the Vaccination Program (%)	Number of Deaths Averted per Season due to the Schoolchildren Vaccination Program
Japan Adjusted Excess P&I:	0.64 (0.49–0.83)	35.90 (16.67–50.74)	992 (355–1825)
USA Adjusted Excess P&I:	1.04 (0.87–1.24)	−4.16 (−23.46–13.04)	_

The period 1978–1994 corresponds to the schoolchildren vaccination program in Japan, which was discontinued after 1994. Vaccine protective effectiveness estimates were calculated as (1-1/RR)×100.