Table 1

Influenza seasons in England and Wales, 1974/1975–2004/2005: dominant variant, antigenic drift events in evoluation of influenza A/H3N2 viruses, vaccine mismatch, vaccine coverage and numbers of excess P&I deaths by age group

Influenza season	Dominant influenza variant(s)	Antigenic drift events30	Vaccine cluster*	Minimum monthly temperature (°C)	Vaccine coverage, 65–74 years (%)	Excess deaths (n), 65–74 years	Vaccine coverage, 75+ years (%)	Excess deaths (n), 75+ years	Vaccine coverage, 45–64 years (%)	Excess deaths (n), 45–64 years
1975/1976	H3N2/B32	EN72-VI75		4.5	0	1910	0	9389	0	863
1976/1977	H3N233			2	0	456	0	2986	0	203
1977/1978	H3N2/H1N132	VI75-TX77		2.8	0	419	0	2563	0	158
1978/1979	B32			−0.4	0	14	0	25	0	0
1979/1980	H3N232	TX77-BA79		2.3	0	0	0	95	0	0
1980/1981	H1N1/H3N232			3	0	89	0	605	0	73
1981/1982	B/H3N234			0.3	0	174	0	501	0	4
1982/1983	H3N234			1.7	0	264	0	1947	0	48
1983/1984	H1N1/B34			3.3	0	88	0	742	0	38
1984/1985	H3N2/B34			0.8	0	74	0	395	0	5
1985/1986	B35			−1.1	0	0	0	0	0	14
1986/1987	H1N135			0.8	0	0	0	0	0	0
1987/1988	H3N2/H1N136	BA79-SI87		4.9	0	0	0	5	0	4
1988/1989	H1N1/H3N236			5.2	0	374	0	2023	0	119
1989/1990	H3N236	SI87-BE89	SI8737	4.9	22	2007	27	14115	9	638
1990/1991	B36		BE8938	1.5	24	0	31	178	9	0
1991/1992	H3N236		BE8939	3.7	27	413	33	3302	10	111
1992/1993	B/H1N136	BE89-BE92	BE8940	3.6	26	0	33	0	10	0
1993/1994	H3N236		BE9241	3.2	32	557	39	4238	12	137
1994/1995	B36		BE9242	4.8	33	0	40	0	12	0
1995/1996	H3N236	BE92-WU95	BE9243	2.3	33	651	42	5365	12	226
1996/1997	H3N236		WU9544	2.5	33	0	41	15	12	9
1997/1998	H3N2/H1N145	WU95-SY97	WU9545	5.2	38	0	46	9	14	10
1998/1999	H3N2/B46		SY9746	5.3	37	628	49	6802	13	233
1999/2000	H3N247		SY9747	4.9	40	1083	53	10554	14	560
2000/2001	B/H1N148		SY9748	3.2	59†	0	74†	109	16	0
2001/2002	H3N2/H1N249		SY9749	3.6	61†	21	76†	0	17	0
2002/2003	B/H3N250	SY97-FU02	SY9750	3.9	63†	0	78†	0	17	10
2003/2004	H3N251		SY9751	4.8	65†	338	82†	2704	18	152
2004/2005	H3N252		FU0252	4.3	64†	1	81†	27	NA	9

*Italics indicate a mismatch between a vaccine and a dominant circulating A/H3N2-virus cluster.
†Estimated from coverage 65+ years and mean ratio of coverage in the 65–74 to 65+ years age group and the 75+ to 65+ years age group for 1989/1990–1999/2000.
NA, not applicable; P&I, pneumonia or influenza.