Table 2.

Cox Regression Table. Hazard ratios > 1 mean that the comparator group was published faster than the control group. Univariate models were conducted using Cox proportional hazards models with a single predictor of timeliness. Variables that were significant predictors of timeliness in univariate analysis were included in multivariate Cox regression. Overall risk of bias was not included to avoid collinearity with individual items evaluating data representativeness and quality. The overall multivariate p value was < 2e-16 according to the Wald test.

Reference group	Comparison group	Univariate Cox regression hazard ratio [95 % CI]	Univariate Cox regression p value	Multivariate Cox regression hazard ratio [95 % CI]	Multivariate Cox regression p value
Publication Venue -Journal article (peer-reviewed)	Media	20.4 [16.4–25.3]	< 2e-16 ***	17.0 [13.3–21.8]	< 2e-16 ***
	Institutional Report	12.2 [10.1–14.8]	< 2e-16 ***	12.4 [10.1–15.1]	< 2e-16 ***
	Preprint	2.3 [2.0–2.5]	< 2e-16 ***	2.2 [2.0–2.5]	< 2e-16 ***
	Presentation or Conference	1.3 [1.0–1.8]	0.05	1.3 [0.96–1.7]	0.09
Sample Frame -Household and community samples	Blood donors or residual sera	0.76 [0.65–0.88]	3.7e-04 ***	0.88 [0.74–1.05]	0.15
	Healthcare workers and caregivers	0.58 [0.51–0.66]	< 2e-16***	0.81 [0.70–0.94]	0.004 **
	Other special populations	0.58 [0.51–0.66]	< 2e-16***	0.74 [0.64–0.86]	6e-05 ***
	Multiple populations	0.69 [0.58–0.82]	1.7e-05 ***	0.90 [0.74–1.08]	0.26
WHO Region -AMRO	AFRO	1.13 [0.89–1.43]	0.30	1.17 [0.92–1.49]	0.19
	EMRO	0.77 [0.62–0.95]	0.02 *	0.84 [0.68–1.05]	0.14
	EURO	0.85 [0.77–0.95]	0.004 **	0.95 [0.85–1.06]	0.33
	SEARO	1.09 [0.91–1.31]	0.35	1.03 [0.86–1.25]	0.73
	WPRO	0.87 [0.72–1.06]	0.17	0.90 [0.74–1.10]	0.30
Was the sample representative of the target population? -Yes	No	0.96 [0.87–1.06]	0.43	1.10 [0.99 − 1.22]	0.09
	Unclear	1.30 [1.11–1.53]	0.001 **	1.07 [0.90–1.27]	0.45
Was there appropriate sample coverage? -Yes	No	0.83 [0.71–0.98]	0.03 *	0.85 [0.72–1.00]	0.06
	Unclear	1.04 [0.93–1.16]	0.48	1.01 [0.90 − 1.14]	0.82
Did the antibody test used meet FDA EUA standards? -Yes	No	1.09 [0.91–1.32]	0.35	1.01 [0.83–1.22]	0.92
	Unclear	1.24 [1.13–1.36]	8.5e-06 ***	1.08 [0.98–1.19]	0.14
Was appropriate sampling or a population adjustment performed? -Yes	No	0.77 [0.67–0.89]	3.6e-04 ***	1.20 [1.03–1.41]	0.02 *
Geographical Scope -National	Regional	0.88 [0.75–1.03]	0.099	Not included	Not included
	Local	0.93 [0.82–1.05]	0.23	Not included	Not included
Overall Risk of Bias -Low	Moderate	1.13 [0.87–1.47]	0.34	Not included	Not included
	High	1.12 [0.87–1.44]	0.38	Not included	Not included
	Unclear	2.22 [1.65–2.99]	1.2e-07 ***	Not included	Not included

Levels of Significance * - < 0.05; ** < 0.01; *** - < 0.001