Recombinant chimeric bovine/human parainfluenza virus 3 expressing sars-cov-2 spike protein and its use

A recombinant chimeric bovine/human parainfluenza virus 3 (rB/HPIV3), comprising:

• a genome comprising, in a 3′ to 5′ order, a 3′ leader region, a BPIV3 N gene, a heterologous gene, BPIV3 P and M genes, HPIV3 F and HN genes, a BPIV3 L gene, and a 5′ trailer region;
• wherein the heterologous gene encodes a recombinant SARS-COV-2 S protein comprising K986P and V987P substitutions and an amino acid sequence at least 90% identical to SEQ ID NO:
• 22;
• wherein the HPIV3 HN gene encodes a HPIV3 HN protein comprising threonine and proline residues at positions 263 and 370, respectively, with reference to SEQ ID NO:
• 7;
• and
• wherein the recombinant B/HPIV3 is infectious, attenuated, and self-replicating.