Recombinant hMPV harboring a deletion in M2-2 gene was recovered from rhMPV/ΔM2-2 cDNA. The M2-2 deletion was designed to preserve the native ORF of M2-1, which overlaps the M2-2 ORF by 51 nucleotides. The first 21 amino acids of the putative M2-2 protein and the entire M2/SH non-coding region (NCR) were maintained ( Figure 1A ). Recombinant rhMPV/ΔM2-2 was efficiently recovered. RT-PCR was performed on the recovered rhMVP/ΔM2-2 virus to confirm the presence of the M2-2 deletion.