  We examine the leading effects of two-body weak currents from chiral
effective field theory on the matrix elements governing neutrinoless
double-beta decay. In the closure approximation these effects are generated by
the product of a one-body current with a two-body current, yielding both two-
and three-body operators. When the three-body operators are considered without
approximation, they quench matrix elements by about 10%, less than suggested by
prior work, which neglected portions of the operators. The two-body operators,
when treated in the standard way, can produce much larger quenching. In a
consistent effective field theory, however, these large effects become
divergent and must be renormalized by a contact operator, the coefficient of
which we cannot determine at present.
