In a first aspect, the present invention relates to an isolated nucleic acid molecule, in particular, an RNA molecule containing particular substitutions. In a further aspect, the present invention relates to a composition comprising the same as well as virus-like particle, viral vector or virus particle containing the nucleic acid molecule according to the present invention. The virus-like particle, the viral vector or the virus particle is suitable for use as a medicament in particular for treating viral infection. Further, a pharmaceutical composition is provided in particular suitable for use as a pharmaceutical prophylactic vaccine containing the virus-like particle, viral vector or the virus particle or the nucleic acid molecule according to the present invention. Finally, a vaccine for vaccination against viral infection, in particular, influenza viral infection is provided as well as a composition or kit comprising the virus-like particle, viral vector or the virus particle according to the present invention or the nucleic acid molecule according to the present invention in a combination with a wild type viral vector or wild type virus particle said composition or kit is suitable for use in treating or protecting against viral infection.