Influenza: Can we cope better with the unpredictable?

Figures & data

Table 1. United States: Antigenic match between seasonal trivalent influenza vaccine strains and circulating influenza viruses from 2000-01 to 2014-15.*^7,8

	TIV composition: northern hemisphere^5			Circulating viruses: United States
				% of all positive specimens		% of Type A (with subtyping performed) predominant strain (with characterisation performed)		% of Type B lineages predominant strain (with characterisation performed)
Season	A(H1N1)	A(H3N2)	Type B	A	B	A/H1N1	A/H3N2	Yamagata	Victoria
2014-15	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	83.5%	16.5%	0.4%	99.6%	71.9%	28.1%
(week 20)						A/California/7/2009 (100%)	A/Switzerland/9715293/201 (predominant)	B/Massachusetts/2/2012 (98.1%)	B/Brisbane/60/2008 (97.8%)
							A/Texas/50/2012 (18.6%)
2013-14	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	87.4%	12.6%	90.3%	9.7%	72.9%	27.1%
						A/California/7/2009 (99.9%)	A/Texas/50/2012 (95.3%)	B/Massachusetts/2/2012 (99.0%)	B/Brisbane/60/2008 (100%)
2012-13	A/California/7/2009pdm09	A/Victoria/361/2011	B/Wisconsin/1/2010 (YAM)	70.0%	30.0%	6.0%	94.0%	63.8%	36.2%
						A/California/7/2009 (98.7%)	A/Victoria/361/2011 (99.6%)	B/Wisconsin/1/2010 (100%)	Not specified
2011-12	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	82.0%	18.0%	25.0%	73.0%	48.0%	52.0%
						A/California/7/2009 (96.0%)	A/Perth/16/2009 (75.0%)	B/Wisconsin/01/2010 (100%)	B/Brisbane/60/2008 (95.0%)
							A/Victoria/361/2011 (3.0%)
2010-11	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	74.0%	26.0%	38.0%	62.0%	5.8%	94.0%
						A/California/7/2009 (99.8%)	A/Perth/16/2009 (96.8%)	Not specified	B/Brisbane/60/2008 (99.9%)
2009-10	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Brisbane/60/2008 (VIC)	99.0%	1.0%	95.0%	4.0%	11.6%	88.4%
						A/California/7/2009 (99.5%)	A/Perth/16/2009 (100%)	Not specified	B/Brisbane/60/2008 (100%)
2008-09	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Florida/4/2006 (YAM)	66.0%	34.0%	87.0%	13.0%	17.0%	83.0%
						A/Brisbane/59/2007 (100%)	A/Brisbane/10/2007 (100%)	B/Florida/04/2006 (100%)	Not specified
2007-08	A/Solomon Islands/3/2006	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	71.0%	29.0%	26.0%	74.0%	98.0%	2.0%
						A/Solomon Islands/3/2006 (66.0%)	A/Brisbane/10/2007 (60.0%) A/Wisconsin/67/2005 (23.0%)	B/Florida/4/2006 (89.0%)	B/Ohio/01/2005** (75.0%)
						A/Brisbane/59/2007 (29.0%)
2006-07	A/New Caledonia/20/99	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	79.2%	20.8%	62.3%	37.7%	23.0%	77.0%
						A/New Caledonia/20/99 (90.0%)	A/Wisconsin/67/2005 (24.0%)	Not specified	B/Ohio/01/2005** (50.0%)
2005-06	A/New Caledonia/20/99	A/California/7/2004	B/Shanghai/361/2002 (YAM)	79.7%	20.3%	8.1%	91.9%	18.7%	81.3%
						A/New Caledonia/20/99 (97.0%)	A/California/07/2004 (72.8%) A/Wisconsin/67/2005	B/Florida/07/2004 (81.7%) B/Shanghai/361/2002 (16.7%)	B/Ohio/1/2005 (99.9%)
2004-05	A/New Caledonia/20/99	A/Fujian/411/2002	B/Shanghai/361/2002 (YAM)	75.4%	24.6%	0.3%	99.7%	74.4%	25.6%
						A/New Caledonia/20/99 (100%)	A/California/7/2004 (78.0%) A/Wyoming/3/2003** (22.0%)	B/Shanghai/361/2002 (83.0%)	Not specified
2003-04	A/New Caledonia/20/99	A/Moscow/10/99	B/HongKong/330/2001 (VIC)	99.0%	1.0%	0.1%	99.9%	93.0%	7.0%
						Not specified	A/Fujian/411/2002 (H3N2) (88.8%)	B/Sichuan/379/99 (100%)	B/Hong Kong/330/2001 (100%)
							A/Panama/2007/99** (11.2%)
2002-03	A/New Caledonia/20/99	A/Moscow/10/99	B/HongKong/330/2001 (VIC)	56.4%	43.6%	70.3%	29.7%	0.4%	99.6%
						A/New Caledonia/20/99 (100%)	A/Panama/2007/99** (85.0%)	B/Shizuoka/15/2001	B/Hong Kong/330/01
2001-02	A/New Caledonia/20/99	A/Moscow/10/99	B/Sichuan/379/99 (YAM)	87.5%	12.5%	1.9%	98.1%	22.8%	77.2%
						A/New Caledonia/20/99 (100%)	A/Panama/2007/99** (100%)	B/Sichuan/379/99 (21.3%)	Not specified
								B/Shizuoka/15/2001 (predominant)
2000-01	A/New Caledonia/20/99	A/Moscow/10/99	B/Beijing/184/93 (YAM)	54.0%	46.0%	97.0%	3.0%	100%
						A/New Caledonia/20/99 (95.0%)	A/Panama/2007/99** (100%)	B/Beijing/184/93 (11.0%)
						A/Bayern/07/95 (5.0%)		B/Sichuan/379/99** (89.0%)

* For influenza A, mismatch accounting for at least 40% of A-viruses antigenically characterised are indicated in yellow shading. For influenza B, co-circulation or mismatch accounting for at least 40% of B-viruses antigenically characterised are indicated in dark shading

**Viruses characterised that were antigenically similar to the strains specified by the WHO, for example A/Panama/2007/99 is an A/Moscow/10/99 (H3N2)-like virus.

†As from 2013-14 WHO recommends that quadrivalent seasonal influenza vaccines contain a second influenza B virus strain: in 2013-14 and 2014-15 this was a B/Brisbane/60/2008-like virus (VIC)

YAM = Yamagata lineage, VIC = Victoria lineage.

Table 2. Canada: Antigenic match (yellow shading) between seasonal trivalent influenza vaccine strains and circulating influenza viruses from 2000-01 to 2014-15.*⁹

	TIV composition: northern hemisphere ^5			Circulating viruses: Canada
				% of all positive specimens		% of Type A (with subtyping performed) predominant strain (with characterisation performed)		% of Type B lineages predominant strain (with characterisation performed)
Season	A(H1N1)	A(H3N2)	Type B	Influenza A	Influenza B	A/H1N1	A/H3N2	Yamagata	Victoria
2014-15	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	80.6%	19.4%	0.8%	99.2%	92.5%	7.5%
(week 20)						A/California/7/2009 (100%)	A/Switzerland/9715293/2013 (97.0%)	B/Massachusetts/2/2012 (99.6%)	B/Brisbane/60/2008 (100%)
							A/Texas/50/2012 (0.5%)
2013-14	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	73.7%	26.3%	94.0%	6.0%	96.6%	3.4%
						A/California/7/2009 (100%)	A/Texas/50/2012 (99.0%)	B/Massachusetts/2/2012 (100%)	B/Brisbane/60/2008 (100%)
2012-13	A/California/7/2009pdm09	A/Victoria/361/2011	B/Wisconsin/1/2010 (YAM)	85%	15%	12.0%	88.0%	77.0%	23%
						A/California/7/2009 (100%)	A/Victoria/361/2011 (100%)	B/Wisconsin/1/2010 (100%)	B/Brisbane/60/2008 (100%)
2011-12	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	47%	53%	31.0%	69.0%	52.3%	47.7%
						A/California/7/2009 (97.7%)	A/Perth/16/2009 (91.4%)	B/Wisconsin/01/2010 (100%)	B/Brisbane/60/2008 (100%)
2010-11	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	84.5%	15.5%	14.0%	86.0%	4.9%	95.1%
						A/California/7/2009 (98.7%)	A/Perth/16/2009 (98.9%)	B/Wisconsin/01/2010 (100%)	B/Brisbane/60/2008 (100%)
2009-10	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Brisbane/60/2008 (VIC)	99.9%	0.1%	99.9%	0.2%	14.3%	85.7%
						A/California/7/2009 (99.7%)	A/Perth/16/2009 (80.0%)	B/Florida/4/2006	B/Brisbane/60/2008 (71.4%)
						A/Brisbane/59/2007 (0.4%)	A/Brisbane/10/2007 (20.0%)		B/Malaysia/2506/2004 (14.3%)
2008-09	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Florida/4/2006 (YAM)	83.3%	16.7%	96.0%	4.0%	1.9%	98.1%
						A/Brisbane/59/2007 (43.9%)	A/Brisbane/10/2007 (100%)	B/Florida/4/2006 (100%)	B\/Malaysia/2506/2004 (66.5%)
						A/California/07/2009 (56.1)			B/Brisbane/60/2008 (31.6%)
2007-08	A/Solomon Islands/3/2006	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	57.5%	42.5%	35.9%	64.1%	97.5%	2.5%
						A/Solomon Islands/3/2006 (94.8%)	A/Brisbane/10/2007 (94.3%)	B/Florida/4/2006 (100%)	B/Malaysia/2506/2004 (100%)
						A/Brisbane/59/2007 (5.2%)	A/Wisconsin/67/2005 (5.7%)
2006-07	A/New Caledonia/20/99	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	86.2%	13.8%	27.0%	61.4%	89.9%	10.1%
						A/New Caledonia/20/99 (100%)	A/Wisconsin/67/2005 (85.4%)	B/Shanghai/361/2002 (100%)	B/Malaysia/2506/2004 (100%)
2005-06	A/New Caledonia/20/99	A/California/7/2004	B/Shanghai/361/2002 (YAM)	61.1%	38.9%	9.6%	44.6%	1.5%	98.5%
						A/New Caledonia/20/99 (100%)	A/California/07/2004 (87.6%)	B/Shanghai/361/2002 (100%)	B/Malaysia/2506/2004 (70.8%)
							A/Wisconsin/67/2005 (12.4%)		B/Hong Kong/330/2001 (29.2%)
2004-05	A/New Caledonia/20/99	A/Fujian/411/2002	B/Shanghai/361/2002 (YAM)	83.6%	16.4%	1.0%	99.0%	79.0%	21.0%
						Not specified	A/Fujian/411/02 (57.0%)	B/Shanghai/361/2002 (100%)	B/Hong Kong/ 330/01 (100%)
							A/California/7/2004 (43.0%)
2003-04	A/New Caledonia/20/99	A/Moscow/10/99	B/Hong Kong/330/2001 (VIC)	98.7%	1.2%	0.4%	94.8%	82.5%	17.5%
						A/New Caledonia/20/99(100%)	A/Fujian/411/2002 (96.8%)	B/Sichuan/379/99 (100%)	B/Hong Kong/330/01 (100%)
							A/Panama/2007/99** (3.1%)
2002-03	A/New Caledonia/20/99	A/Moscow/10/99	B/Hong Kong/330/2001 (VIC)	58.0%	42.0%	23.0%	16.0%	Not specified	B/Hong Kong/330/01 (predominant)
						A/New Caledonia/20/99 [77% H1N2] §	A/Panama/2007/99**(100%)
2001-02	A/New Caledonia/20/99	A/Moscow/10/99	B/Sichuan/379/99 (YAM)	87.0%	13.0%	0.2%	82.0%	3.3%	96.7%
						A/New Caledonia/20/99 [17.7% H1N2] §	A/Panama/2007/99** (100%)	B/Sichuan/379/99 (100%)	B/Hong Kong/330/01 (100%)
2000-01	A/New Caledonia/20/99	A/Moscow/10/99	B/Beijing/184/93 (YAM)	32.0%	68.0%	99.4%	0.6%	99.6%	0.4%
						A/New Caledonia/20/99 (97.0%) A/Johannesburg/82/96 (1.0%)	A/Panama/2007/99** (100%)	B/Yamanashi/166/98** (100%)	B/Beijing/243/97(100%)

* For influenza A, mismatch accounting for at least 40% of A-viruses antigenically characterised are indicated in yellow shading. For influenza B, co-circulation or mismatch accounting for at least 40% of B-viruses antigenically characterised are indicated in dark shading

**Viruses characterised that were antigenically similar to the strains specified by the WHO, for example A/Panama/2007/99 is an A/Moscow/10/99 (H3N2)-like virus.

†As from 2013-14 WHO recommends that quadrivalent seasonal influenza vaccines contain a second influenza B virus strain: in 2013-14 and 2014-15 this was a B/Brisbane/60/2008-like virus (VIC)

YAM = Yamagata lineage, VIC = Victoria lineage.

§ The H1 antigen was identical to the vaccine strain

Table 3. Europe: Antigenic match between seasonal trivalent influenza vaccine strains and circulating influenza viruses from 2000-01 to 2014-15.*¹¹

	TIV composition: northern hemisphere ^5			Circulating viruses: Europe
	A(H1N1)	A(H3N2)	Type B	% of all positive specimens		% of Type A (with subtyping performed) predominant strain (with characterisation performed)		% of Type B lineages predominant strain (with characterisation performed)
Season				A	B	A/H1N1	A/H3N2	Yamagata	Victoria
2014-15	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	67%	33%	23.1%	76.9%	97.7%	2.3%
(week 20)						A/California/07/2009	A/Switzerland/9715293/2013 (71.0% of H3)	B/Massachusetts/02/2012 (19.9% of YAM)	B/Brisbane/60/2008 (100% of VIC)
							A/Texas/50/2012 (29.0% of H3)	B/Phuket/3073/2013 (79.2% of YAM) B/Wisconsin/1/2010 (0.1% of YAM)
								B/Florida/4/2006 (0.7% of YAM)
2013-14	A/California/7/2009pdm09	A/Texas/50/2012	B/Massachusetts/2/2012 (YAM)†	98%	2%	A/California/07/2009	A/Texas/50/2012	69.5%	30.5%
						(60.0% of all)	(37.0% of all)	B/Wisconsin/1/2010 (12.2% of YAM)	B/Brisbane/60/2008(100% of VIC)
								B/Massachusetts/02/2012 (85.4% of YAM)
2012-13	A/California/7/2009pdm09	A/Victoria/361/2011	B/Wisconsin/1/2010 (YAM)	48.5%	51.5%	58.0%	42.0%	86.0%	14.0%
						A/California/07/2009	A/Victoria/361/2011	B/Wisconsin/1/2010 (25.0% of all)	B/Brisbane/60/2008
						(9.5% of all)	(55.0% of all)	B/Florida/4/2006 (0.5% of all)	(6.6% of all)
2011-12	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	89.3%	10.7%	1.5%	98.5%	39.6%	60.4%
						A/California/07/2009	A/Perth/16/2009 (74.3%)	not specified	not specified
							(58.1% of A/H3 viruses had an imperfect genetic match with vaccine strain)
2010-11	A/California/7/2009	A/Perth/16/2009	B/Brisbane/60/2008 (VIC)	59.6%	40.4%	97.0%	3.0%	<10%	B/Brisbane/60/20089
						A/California/07/2009	A/Perth/16/2009	B/Florida/4/2006	(Predominant)
								B/Bangladesh/3333/2007
2009-10	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Brisbane/60/2008 (VIC)	99%	1%	A/California/07/2009 (99.7% of all)	<0.1% of all	Not specified	Not specified
2008-09	A/Brisbane/59/2007	A/Brisbane/10/2007	B/Florida/4/2006 (YAM)	81.4%	18.6%	A/Brisbane/59/2007 (3.7% of all)	A/Brisbane/10/2007 (37.1% of all)	B/Florida/4/2006 (0.8% of all)	B/Malaysia/2506/2004 (20.7% of all)
									B/Brisbane/60/2008 (1.6% of all)
2007-08	A/Solomon Islands/3/2006	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	60%	40%	A/Solomon Islands/3/2006 (58.0% of all)	A/Brisbane/10/2007 (1.5% of all)	B/Florida/4/2006 predominant (38.0% of all)	B/Malaysia/2506/2004 (0.5% of all)
						A/New Caledonia/20/99 (1.5% of all)	A/Wisconsin/67/2005 (0.8% of all)
2006-07	A/New Caledonia/20/99	A/Wisconsin/67/2005	B/Malaysia/2506/2004 (VIC)	97.2%	2.8%	10.7%	89.3%	B/Jiangsu/10/2003 (1.0% of all)	B/Malaysia/2506/2004 (4.0% of all)
						A/New Caledonia/20/99 (8.0% of all)	A/Wisconsin/67/2005 (86.0% of all)
							A/California/7/2004 (1.0% of all)
2005-06	A/New Caledonia/20/99	A/California/7/2004	B/Shanghai/361/2002 (YAM)	42.0%	58.0%	48.0%	51.8%	Not specified	Not specified
						Not specified	Not specified
2004-05	A/New Caledonia/20/99	A/Fujian/411/2002	B/Shanghai/361/2002 (YAM)	83.3%	16.7%	18.2%	81.8%	Not specified	43.0%
						Not specified	A/Wellington/1/2004		B/Hong Kong/330/2001
							A/California/7/2004
2003-04	A/New Caledonia/20/99	A/Moscow/10/99	B/HongKong/330/2001 (VIC)	99.1%	0.9%	0.5%	99.1%	Not specified	Not specified
						Not specified	Not specified
2002-03	A/New Caledonia/20/99	A/Moscow/10/99	B/HongKong/330/2001 (VIC)	63.4%	36.4%	9.7%	88.8%	Not specified	Not specified
						Not specified	Not specified
2001-02	A/New Caledonia/20/99	A/Moscow/10/99	B/Sichuan/379/99 (YAM)	74.9%	25.1%	3.8%	87.3%	Not specified	Not specified
						Not specified	Not specified
2000-01	A/New Caledonia/20/99	A/Moscow/10/99	B/Beijing/184/93 (YAM)	70.3%	29.7%	96.7%	3.1%	Not specified	Not specified
						Not specified	Not specified

* For influenza A, mismatch accounting for at least 40% of A-viruses antigenically characterised are indicated in yellow shading. For influenza B, co-circulation or mismatch accounting for at least 40% of B-viruses antigenically characterised are indicated in dark shading

†As from 2013-14 WHO recommends that quadrivalent seasonal influenza vaccines contain a second influenza B virus strain: in 2013-14 and 2014-15 this was a B/Brisbane/60/2008-like virus (VIC)

YAM = Yamagata lineage, VIC = Victoria lineage.

(X% of all) = percentage of all viruses (A +B) that were antigenically subtyped

% of A/B etc = percentage of all viruses subtyped as ‘A’ or ‘B’ etc

Note that numbers were derived from EU reports which summarise data from the different EU countries in which the virus circulation was not always perfectly homogenous.

Table 4. Influenza vaccine effectiveness in the 2014-15 northern hemisphere season.

Country	Outcome measure	Population	VE (95% CI)
United States ^20	Laboratory-confirmed, medically attended acute respiratory illness	6 months -17 years	24% (0; 43)
		18-49 years	16% (−18; 41)
		≥ 50 years	23% (−14 ; 47)
United Kingdom ^21	Primary care consultation with laboratory-confirmed influenza	All ages	3.4% (44.8; 35.5)*
	Primary care consultation with laboratory-confirmed A/H3N2 influenza	All ages	2.3% (−56.2; 33.0)*
Canada ^22	Laboratory-confirmed, medically attended influenza	All ages	−4% (−45; 25)
	Laboratory-confirmed, medically attended A/H3N2 influenza	All ages	−8% (−50; 23)
Canada ^19	Laboratory-confirmed influenza-related hospitalisation	≥ 16 years**	−16.8% (−48.9; 8.3)†
		< 65 years**	10.8% (−50.2; 47.0)†
		≥ 65 years**	−25.4% (−65.0; 4.6) †

*adjusted for age group, sex, month, surveillance scheme and primary school area.

**Adjusted for age and co-morbidity.

† 90% CI