Table 1.

 Study characteristics

Study	Influenza season	Age at enrollment	n	Control	Geographic location
1, year 1, Belshe	1996–1997	15–71 months	1602	Placebo	United States
1, year 2, Belshe	1997–1998	27–83 months	1358	Placebo	United States
2, Belshe	2004–2005	6–59 months	7852	TIV	Global
3, Ashkenazi	2002–2003	6–71 months	2085	TIV	Europe/Israel
4, Fleming	2002–2003	6–17 years	2202	TIV	Europe/Israel

LAIV, live attenuated influenza vaccine; TIV, trivalent inactivated influenza vaccine.