  We report Very Large Array (VLA) observations in the Q-band toward 10 ionized
jet candidates to search for SiO emission, a well-known shocked gas tracer. We
detected 7 mm continuum counterparts toward 90% of the jet candidates. In most
cases, the jet candidate is located toward the center of the 7 mm core, and the
high masses ($\approx 100\,M_\odot$) and densities ($\approx 10^7\,
\text{cm}^{-3}$) of the cores suggest that the central objects are very young
high-mass protostars. We detected SiO $J=1-0$ emission associated with 6 target
sources. In all cases, the morphology and spectrum of the emission is
consistent with what is expected for molecular jets along an outflow axis, thus
confirming the jet nature of 60% of our sample. Our data suggest a positive
correlation between the SiO luminosity $L_{SiO}$, and both the bolometric
luminosity $L_{Bol}$ and the radio luminosity $S_\nu d^2$ of the driving
sources.
