Human metapneumovirus (HMPV), a single-stranded negative-sense RNA virus 
belonging to the family Paramyxoviridae, is associated with respiratory tract 
illness, primarily in young children and persons with underlying disease. Based 
on genetic and antigenic variation, HMPV strains are classified into two 
serotypes, with isolates NL/1/00 and NL/1/99 as prototypes for serotypes A and 
B, respectively. The development of plasmid-based reverse genetics systems for 
both serotypes has resulted in developments of a wide range of vaccine 
candidates against HMPV infection. The approach to virus rescue of HMPV is 
similar to that used for other paramyxoviruses, starting with mini-replicon 
assays for optimizations of the rescue protocols and subsequent replacement of 
the mini genome with a plasmid expressing the cDNA of the full-length viral RNA 
genome. Here, we provide detailed information on the reverse genetics systems 
for HMPV.