Safety, Immunogenicity, And Efficacy Of Ndv-3a Against Staphylococcus Aureus Colonization: A Phase 2 Vaccine Trial Among Us Army Infantry Trainees

Publication Type
Journal Article
Year of Publication
Millar, Eugene V; Bennett, Jason W; Barin, Burc; Carey, Patrick M; Law, Natasha N; English, Caroline E; Schwartz, Michael M; Cochrane, Terrence; Ellis, Michael W; Tribble, David R; Timothy Cooke, M; Hennessey, John P
Date Published
2021 05 27
CRID; Humans; Immunogenicity, Vaccine; Military Personnel; Staphylococcal Infections; Staphylococcal Vaccines; Staphylococcus aureus; Vaccines

BACKGROUND: Military trainees are at increased risk for Staphylococcus aureus colonization and infection. Disease prevention strategies are needed, but a S. aureus vaccine does not currently exist.

METHODS: We enrolled US Army Infantry trainees (Fort Benning, GA) in a phase 2, randomized, double-blind, placebo-controlled trial of NDV-3A, a vaccine containing a recombinant adhesin/invasion protein of Candida albicans that has structural similarity to the S. aureus protein clumping factor A. Study participants received one intramuscular dose of NDV-3A or placebo (adjuvant alone) within 72 h of arrival on base. Longitudinal nasal and oral (throat) swabs were collected throughout the 14-week Infantry training cycle. Safety, immunogenicity, and efficacy of NDV-3A against S. aureus nasal / oral acquisition were the endpoints.

RESULTS: The NDV-3A candidate had minimal reactogenicity and elicited robust antigen-specific B- and T-cell responses. During the 56-day post-vaccination period, there was no difference in the incidence of S. aureus nasal acquisition between those who were randomized to receive NDV-3A vs. placebo (25.6% vs. 29.1%; vaccine efficacy [VE]: 12.1%; p = 0.31). In time-to-event analysis, there was no difference between study groups with respect to the S. aureus colonization-free interval (VE: 13%; p = 0.29). Similarly, the efficacy of NDV-3A against S. aureus oral acquisition was poor (VE: 2.4%; p = 0.52).

CONCLUSIONS: A single dose of NDV-3A did not prevent nasal nor oral acquisition of S. aureus in a population of military trainees at high risk for colonization.