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Using an updated and significantly augmented sample of Cepheid and TRGBdistances to 28 nearby spiral and irregular galaxies, covering a wide range ofmetallicities, we have searched for evidence of a correlation of the zero-pointof the Cepheid Period-Luminosity relation with HII region (gas-phase)metallicities. Our analysis, for the 21 galaxies closer than 12.5 Mpc, resultsin the following conclusions: (1) The zero points of the Cepheid and TRGBdistance scales are in remarkably good agreement, with the mean offset in thezero points of the most nearby distance-selected sample being close to zero,Delta mod_o(Cepheid - TRGB) = -0.026 +\- 0.015 mag (for an I-band TRGB zeropoint of M_I = -4.05 mag); however, for the more distant sample, there is alarger offset between the two distance scales, amounting to -0.073 +/- 0.057mag. (2) The individual differences, about that mean, have a measured scatterof +/- 0.068~mag. (3) We find no statistically significant evidence for ametallicity dependence in the Cepheid distance scale using the reddening-freeW(V,VI) period-luminosity relation:  Delta mod_o (Cepheid - TRGB) = -0.022 (+/- 0.015) \times ([O/H]-8.50) - 0.003(+/- 0.007)

Systematics in the Cepheid and TRGB Distance Scales: Metallicity Sensitivity of the Wesenheit Leavitt Law