Table 1.

Components of the main inference model (described by equations (3) and (4))

Component	Role
Mc (t)	Weekly mortality underlying a specific cause, or a collection of causes
H 31 (t)	Weekly incidence proxy for influenza A/H3N2 during the 1997–1998 through 2002–2003 seasons (before the appearance of the Fujian A/H3N2 strain)
H 32 (t)	Weekly incidence proxy for influenza A/H3N2 during the 2003–2004 through 2006–2007 seasons (the Fujian A/H3N2 strain)
H 1(t)	Weekly incidence proxy for influenza A/H1N1
B (t)	Weekly incidence proxy for influenza B
S	Forward shift operator (between one and two weeks) relating influenza incidence proxies and mortality
f	Fraction of influenza incidence proxy shifted forward by 1 week in S (with a fraction(1 − f) shifted forward by 2 weeks)
${\beta }_{H3}^1$	Regression coefficient for S (H31)
${\beta }_{H3}^2$	Regression coefficient for S (H32)
βH1	Regression coefficient for S (H1) (omitted in the main inference model)
βB	Regression coefficient for S (B)
Base1 (t)	Weekly periodic annual baseline for mortality (with a period of 52 weeks) before week 23 of 2001 (zero thereafter)
Base2 (t)	Weekly periodic annual baseline for mortality (with a period of 52 weeks) starting week 23 of 2001 (zero before that)
Trend	A (low degree) polynomial in the calendar year
Noise	Difference between the expected and observed mortality