Efficacy, immunogenicity, and safety of a plant-derived, quadrivalent, virus-like particle influenza vaccine in adults and older adults

Researchers believe a plant-based influenza vaccine could potentially address some of the limitations seen with egg-derived and other vaccine formulations.

Researchers believe a plant-based influenza vaccine could potentially address some of the limitations seen with egg-derived and other vaccine formulations. Results from a pair of Phase III studies of a recombinant quadrivalent virus-like particle (QVLP) influenza vaccine manufactured in plants suggest both high tolerance and high efficacy in adults. One of the multinational trials randomized participants aged 18–64 years into two treatment arms, with 5,077 assigned to QVLP vaccine and 5,083 assigned to placebo. The study, conducted during the 2017–18 influenza season, fell short of the main outcome of 70% target threshold for efficacy of the QVLP vaccine against clinically confirmed respiratory illness caused by matched strains. Efficacy was measured at about 35%. The second trial, which took place during the 2018–19 influenza season and focused on people aged 65 years and older, randomized 6,396 participants to QVLP vaccine and 6,398 participants to quadrivalent inactivated vaccine (QIV). The main outcome was relative vaccine efficacy to prevent laboratory-confirmed influenza-like illness caused by any influenza strain, and the pre-specified non-inferiority threshold of 8.8% was met. Significant safety concerns were absent from both trials, demonstrating QVLP as both well-tolerated and effective against respiratory illness and influenza-like illness caused by influenza viruses.