The invention relates to pneumoviral virions comprising a viral genome that has a mutation in a gene coding for a protein that is essential for infectivity of the pneumovirus, whereby the mutation causes a virus produced from only the viral genome to lack infectivity, and whereby the virion comprises the protein in a form and in an amount that is required for infectivity of the virion. The invention also relates to methods for producing the pneumoviral virions and for using the virions in the treatment or prevention of pneumoviral infection and disease. A preferred pneumoviral virion is a virion of Respiratory Syncytial Virus in which preferably the gene for the G attachment protein is inactivated and complemented in trans.

Described herein are RSV polynucleotide sequences that make use of multiple codons that are containing silent nucleotide substitutions engineered in multiple locations in the genome, wherein the substitutions introduce a numerous synonymous codons into the genome. Due to the large number of defects involved, the attenuated viruses disclosed herein provide a means of producing attenuated, live vaccines against RSV.

Provided are a method for inactivating respiratory syncytial virus (RSV) and stabilizing pre-F protein in RSV and inactivated RSV virus obtained thereby. Also provided are a vaccine comprising the inactivated RSV virus and a use of the vaccine in preventing or treating RSV infection or a disease related thereto.

The disclosure relates to Respiratory Syncytial Virus (RSV) vaccine compositions having truncated mucin domains in the G-protein. In certain embodiments, this disclosure relates to virus particles, virus-like particles, virosomes, nucleic acids, vectors, or attenuated live RSV vaccines for uses reported herein. In certain embodiments, this disclosure relates to methods of vaccinating, treating, or preventing RSV infections by administering to a subject in need thereof an effective amount of a composition disclosed herein.