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Table 1 Characteristics of analyzed journal articles with original data

From: Research methodology and characteristics of journal articles with original data, preprint articles and registered clinical trial protocols about COVID-19

Variable (N of denominator)N (%)a
Journals (N = 533)
 Journal of Medical Virology33 (6.1)
 Journal of Infection18 (3.3)
 International Journal of Infectious Diseases16 (3.0)
 Clinical Infectious Diseases15 (2.8)
 Radiology14 (2.6)
 Other437 (82)
Country in the author affiliation (N = 533)
 China402 (75)
 USA62 (12)
 UK21 (3.9)
 Japan20 (3.7)
 Italy19 (3.5)
 Other9 (1.7)
Self-reported study design (N = 312)
 Retrospective study88 (28)
 Case report86 (28)
 Case series46 (15)
 Modelling18 (5.7)
 Systematic review with or without meta-analysis16 (5.1)
 Other58 (18.6)
Thematic classification (N = 456)
 Case reports – patients173 (38)
 Transmission/risk/prevalence104 (23)
 Genetics/biology57 (13)
 Health impacts54 (12)
 Diagnosis41 (9)
 Other27 (5.9)
Country of study funders (N = 268)
 China202 (75)
 USA13 (4.9)
 Japan11 (4.1)
 Korea5 (1.9)
 Canada4 (1.5)
 Other33 (12.3)
  1. aDenominator is provided in the first column, as “N of trials with reported variable”; for some variables due to rounding the sums may not be exact 100%, for variables we presented only five most frequent categories