  We combine JWST observations with ALMA CO and VLT-MUSE H$\alpha$ data to
examine off-spiral arm star formation in the face-on, grand-design spiral
galaxy NGC 628. We focus on the northern spiral arm, around a galactocentric
radius of 3-4 kpc, and study two spurs. These form an interesting contrast, as
one is CO-rich and one CO-poor, and they have a maximum azimuthal offset in
MIRI 21$\mu$m and MUSE H$\alpha$ of around 40$^\circ$ (CO-rich) and 55$^\circ$
(CO-poor) from the spiral arm. The star formation rate is higher in the regions
of the spurs near to spiral arms, but the star formation efficiency appears
relatively constant. Given the spiral pattern speed and rotation curve of this
galaxy and assuming material exiting the arms undergoes purely circular motion,
these offsets would be reached in 100-150 Myr, significantly longer than the
21$\mu$m and H$\alpha$ star formation timescales (both <10 Myr). The invariance
of the star formation efficiency in the spurs versus the spiral arms indicates
massive star formation is not only triggered in spiral arms, and cannot simply
occur in the arms and then drift away from the wave pattern. These early JWST
results show that in-situ star formation likely occurs in the spurs, and that
the observed young stars are not simply the `leftovers' of stellar birth in the
spiral arms. The excellent physical resolution and sensitivity that JWST can
attain in nearby galaxies will well resolve individual star-forming regions and
help us to better understand the earliest phases of star formation.
