Influenza epidemiology and influenza vaccine effectiveness during the 2014–2015 season: annual report from the Global Influenza Hospital Surveillance Network

Table 1 Selection of patients and results of RT-PCR

	St. Petersburg		Moscow		Czech Republic		Turkey		Beijing		Valencia		Total
Category	n	%	n	%	n	%	n	%	n	%	n	%	n	%
Screened admissions	3164		1934		123		1409		1425		12,496		20,551
Exclusion criteria
Non resident	21	0.7	95	4.9	12	9.8	73	5.2	5	0.4	50	0.4	256	1.2
Institutionalised	14	0.4	14	0.7	2	1.6	17	1.2	2	0.1	800	6.4	849	4.1
Previous discharge <30 days	31	1.0	51	2.6	8	6.5	216	15.3	13	0.9	2283	18.3	2602	12.7
Unable to communicate	20	0.6	47	2.4	2	1.6	125	8.9	0	0.0	782	6.3	976	4.7
Not giving consent	100	3.2	32	1.7	14	11.4	47	3.3	15	1.1	504	4.0	712	3.5
No ILI symptoms ≥5 years of age	19	0.6	25	1.3	1	0.8	131	9.3	18	1.3	2903	23.2	3097	15.1
Admission within 7 days of symptoms onset	181	5.7	150	7.8	4	3.3	110	7.8	44	3.1	745	6.0	1234	6.0
Previous influenza infection	1	0.0	0	0.0	0	0.0	7	0.5	0	0.0	1	0.0	9	0.0
Onset of symptoms to swab >9 days	0	0.0	1	0.1	0	0.0	2	0.1	0	0.0	1	0.0	4	0.0
Sample inadequate	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	5	0.0	5	0.0
Sample lost	0	0.0	0	0.0	0	0.0	0	0.0	1	0.1	1	0.0	2	0.0
Recruited outside periods with continuous influenza positive admissions	31	1.0	115	5.9	1	0.8	65	4.6	178	12.5	764	6.1	1154	5.6
Included with valid laboratory results	2715	85.8	1400	72.4	79	64.2	614	43.6	1149	80.6	3657	29.3	9614	46.8
RT-PCR result
Influenza negative	2113	77.8	966	69.0	20	25.3	543	88.4	875	76.2	2920	79.8	7437	77.4
Influenza positive	602	22.2	434	31.0	59	74.7	71	11.6	274	23.8	737	20.2	2177	22.6
Subtype and lineage^a
A(H1N1)pdm09	47	7.8	30	6.9	7	11.9	26	36.6	1	0.4	10	1.4	121	5.6
A(H3N2)	267	44.3	163	37.6	33	55.9	6	8.5	163	59.5	611	82.9	1243	57.1
A not subtyped	48	8.0	9	2.1	2	3.3	0	0.0	0	0.0	47	6.4	106	4.9
B/Yamagata lineage	258	42.9	175	40.3	16	27.1	0	0.0	109	39.8	65	8.8	623	28.6
B/Victoria lineage	0	0	10	2.3	0	0	0	0.0	1	0.4	0	0.0	11	0.5
B not subtyped^b	0	0	52	12.0	2	3.4	39	54.9	0	0.0	4	0.5	97	4.5

Abbreviations: ILI, influenza-like disease; RT-PCR, reverse transcriptase-polymerase chain reaction
^aBecause there were 24 mixed infections, each involving two different influenza viruses, the sum by strain may be greater than the number of patients included with lab results. Percentages are reported by total of influenza-positive cases
^bFor Turkey and Valencia, all B not subtyped were assumed to be B/Yamagata lineage based on virus circulation at these sites. This assumption was not applied for Moscow because of a mixed pattern of influenza B circulation

ISSN: 1471-2458