Are Countries Regulating Veterinary Drug Residues That Are Important to Human Health?

Background One Health approach is encouraged when monitoring and regulating antimicrobials that intersect both human and animal medicine. This study develops a novel methodology to assign a “One Health Score” that quantifies how maximum residue limits for drugs set by countries for veterinary purposes align with established international standards. Methods We classify the importance of each antimicrobial drug with a maximum residue limit using criteria outlined by the World Health Organization and the World Organization for Animal Health. We then create a hierarchy of antimicrobial importance that prioritizes human health to illustrate the ranking and focus for each country, drug class, and animal species groups. This ranking is then used to develop a unique “One Health Score” that assesses each country, drug class, and animal species degree of regulatory compliance with the international standard of Codex Alimentarius. Findings: Codex, the European Union, and the United States are identified as leaders of establishing maximum residue limits to which other countries defer to. Among pairs with medical classifications, 53% fall under the pairing of Highly Important Antimicrobials (H3) for humans and Veterinary Critically Important Antimicrobials (V1) for animals. The One Health Score is non-negative for at least 50% of countries at each medical importance level. However, 21% of the countries with H3V1 MRLs are laxer than Codex. Interpretation: Drugs with a high market demand in animal agriculture are the most commonly regulated among countries. This suggests drugs used less in food animals may not be adequately regulated currently, despite, in some cases, being highly important for human health. Country officials must balance economic and health priorities when setting or modifying drug residue limits.