A construction of admissible A1(1)-modules of level -43.

By using generalized vertex algebras associated to rational lattices, we construct explicitly the admissible modules for the affine Lie algebra A1(1) of level -43. As an application, we show that the W(2,5) algebra with central charge c=-7 investigated in (J. Algebra 270 (2003) 115) is a subalgebra of the simple vertex operator algebra L(-43Λ0).