LNP1 and infection: Notably, pigs vaccinated with a single dose of either the LNP1 or LNP2 vaccine mounted high HI antibody titers on day 14 postvaccination and were fully protected against challenge infection with the homologous IAV-S strain, with only one 1 of 12 vaccinated pigs exhibiting a low copy number of viral RNA, ranging from 103.9 to 105 copies/100 μL of nasal swabs, detected on days 3 and 4 post-challenge, respectively.