Figure 7 Funnel plots. (A) Eligibility criteria not mentioned or inappropriate (B) Randomization deficiency (C) Sample/power calculation deficiency (D) Cell line bacterial contamination other than mycoplasma (E). Cell line cross-contamination (F). Misidentified cell lines (G). Mixed contamination of cell lines (H). Mycoplasma cell line contamination (I). Viral contamination of cell lines (J). Chi-square test used when expected cells frequency are <5 (K). Parametric test for non-parametric data and vice versa (L). Related data independent test and vice versa (M). Mean(SD) used for non-normal or ordinal data (N). variability description +/− notation undefined (O). Failure to report exact p-value (P). p-value significance level not defined (Q). p-value reported without statistical test (R). Significance stated without providing statistical test (S). Statistical software not mentioned (T). Statistical test name incorrect (U). Study population baseline characteristics not described (V). Number of tails not stated (W). Reporting of “Where appropriate statement” (X). Statistical test used for dataset not specified.