Recombinant Newcastle disease viruses useful as vaccines or vaccine vectors

An antigenomic RNA of Newcastle disease virus, comprising NP gene, P gene, M gene, F gene, HN gene and L gene in this order from a 5′ to 3′ direction, said antigenomic RNA further comprising n foreign nucleotide complexes inserted (a) before the NP gene, (b) between the P and M genes, and/or (c) between the HN and L genes, wherein n is 1, 2, 3 or 4;

• each of the foreign nucleotide complexes comprising a Newcastle disease virus gene start sequence, an open reading frame of a foreign gene and a Newcastle disease virus gene end sequence in this order from the 5′ to 3′ direction, wherein the foreign gene is a gene not found naturally in the Newcastle disease virus;
• and
• wherein when 2, 3 or 4 foreign nucleotide complexes are inserted together before the NP gene, between the P and M genes, or between the HN and L genes, the foreign nucleotide complexes are sequentially linked directly or indirectly.