Abstract
Haemonchus contortus is a highly pathogenic nematode in small ruminants, causing major production losses and animal welfare concerns. With increasing anthelmintic resistance, vaccination offers a more sustainable control strategy. This study evaluated a novel glycoengineered vaccine produced in Hi5 insect cells in a randomized, controlled trial including Jura × Lacaune sheep. Animals received either Barbervax(®) (BVAX), the glycoengineered vaccine (GEA) composed of five antigens (H11, H11-1, H11-2, H11-4 and GA1), its non-glycoengineered counterpart (NEA), or served as controls. Over 16 weeks, clinical, immunological, and parasitological data were collected. GEA reduced fecal egg counts by 81.09% and worm burden by 25.36%, showing a lower degree of anemia compared to NEA and control. All vaccinated groups exhibited elevated IgG/IgE responses. The results underscore the importance of glycoengineering in achieving protective immunity against H. contortus, supporting the development of highly effective recombinant vaccines against this and other parasitic worms in the future.