Table 1.

Summarized characteristics of the studies included in the meta-analysis

Author	Year of publication	Viral identification method	Specimens	Viral species, n	Patients, n	Quality score1
Takahashi et al. [15]	2013	PCR	Nasopharyngeal swabs	13	167	9
Luchsinger et al. [31]	2013	Culture, IFA, serology, PCR	Serum, sputum, nasopharyngeal aspirate	10	356	6
Wiemken et al. [13]	2013	PCR	Nasopharyngeal swabs	12	393	7
Viasus et al. [14]	2013	RT-PCR	Nasopharyngeal swabs or BALF	13	747	8
Musher et al. [16]	2013	PCR	Nasopharyngeal swabs	7	259	6
Huijskens et al. [17]	2013	RT-PCR	Throat swabs, sputum	14	408	8
Yin et al. [11]	2012	RT-PCR	Throat swabs, sputum	13	215	5
Sangil et al. [18]	2012	PCR	Nasopharyngeal swabs, sputum	12	131	6
Choi et al. [19]	2012	RT-PCR	Nasopharyngeal aspirates, BALF	16	64	6
Johansson et al. [7]	2010	RT-PCR	Nasopharyngeal samples	16	184	5
Cilloniz et al. [20]	2011	PCR, serology	Nasopharyngeal swabs, serum	14	362	4
Shibli et al. [21]	2010	PCR, serology	Nasopharyngeal swabs, serum	8	126	5
Mermond et al. [22]	2010	serology, PCR, IFA	Serum, nasopharyngeal swabs, TBA, BALF or PSB samples	7	137	5
Lieberman et al. [23]	2010	RT-PCR	Oropharyngeal swabs, nasopharyngeal swabs and nasopharyngeal washing	12	183	9
Cao et al. [12]	2010	RT-PCR	Sputum and throat swabs	16	197	6
Diederen et al. [24]	2009	PCR, serology	Throat swabs, sputum	10	242	5
Johnstone et al. [25]	2008	direct fluorescent antigen tests, RT-PCR	Nasopharyngeal swabs	13	193	7
Jennings et al. [26]	2008	PCR, serology, IFA, culture	Nasopharyngeal swabs, serum	11	304	9
Charles et al. [27]	2008	PCR	Nose and throat swabs	8	885	5
Saito et al. [32]	2006	PCR, serology	Sputum and serum	5	232	7
Angeles et al. [28]	2006	RT-PCR, IFA, culture	Nasopharyngeal swabs	12	198	6
Templeton et al. [29]	2005	RT-PCR	Throat washes and throat swab specimens	12	105	8
Macfarlane et al. [30]	2001	PCR, serology, culture	Throat swabs, serum	7	316	7

BALF = Bronchial alveolar lavage fluid; IFA = indirect immunofluorescence assay; PSB = protected specimen brush; RT-PCR = real-time polymerase chain reaction; TBA = tracheobronchial aspirate.

¹Maximum score = 9.