Identification and vaccine efficacy evaluation of a canine coronavirus isolated in central China

Xiaoyu Zhang; Ying Li; Xin Liu; Ming Zhou; Ling Zhao

doi:10.1016/j.vetmic.2026.110879

Identification and vaccine efficacy evaluation of a canine coronavirus isolated in central China

Vet Microbiol. 2026 Jan 10:314:110879. doi: 10.1016/j.vetmic.2026.110879. Online ahead of print.

Authors

Xiaoyu Zhang¹, Ying Li², Xin Liu¹, Ming Zhou³, Ling Zhao⁴

Affiliations

¹ National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Jiangxia Laboratory, Wuhan 430200, China.
² National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
³ National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Jiangxia Laboratory, Wuhan 430200, China; Key Laboratory of Preventive Veterinary Medicine of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
⁴ National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Jiangxia Laboratory, Wuhan 430200, China; Hubei Hongshan Laboratory, Wuhan 430070, China; Key Laboratory of Preventive Veterinary Medicine of Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: lingzhao@mail.hzau.edu.cn.

PMID: 41529644
DOI: 10.1016/j.vetmic.2026.110879

Abstract

Canine coronavirus (CCoV) is a significant enteric pathogen in dogs, particularly in group-housed conditions. Although it is classically associated with mild enteritis, its high mutation rate drives genetic diversification, influencing virulence and reducing the effectiveness of traditional vaccines. To address this challenge, a novel CCoV strain, WH2023, was isolated from a breeding facility in Wuhan, Central China. Phylogenetic analysis of the spike (S) gene suggested that WH2023 is the predominant CCoV-IIa subtype. Pathogenicity studies in puppies revealed high virulence, with 100 % morbidity after a high challenge dose (10⁶ TCID₅₀/mL), severe diarrhea and lethargy, intestinal lesions in the jejunum and ileum, and high viral loads consistent with typical CCoV pathogenesis. An inactivated vaccine based on WH2023 and formulated with the GEL02 adjuvant was developed and evaluated in beagle puppies. Safety assessments revealed an excellent profile, and immunogenicity studies revealed strong neutralizing antibody responses, reaching titers of 1:5404 (12.4 log2) one week after booster vaccination. Vaccinated dogs were fully protected against the WH2023 challenge, whereas unvaccinated controls developed gastroenteritis. Neutralizing antibody titers in vaccinated dogs remained above 1:32 for up to 300 days and significantly exceeded those induced by commercial vaccines available in China. These findings indicate that WH2023 is a highly virulent CCoV-IIa strain and a promising candidate for vaccine development, providing enhanced safety and long-lasting protection against canine coronavirus infection.

Keywords: CCoV-IIa subtype; Canine coronavirus; Inactivated vaccines; Isolation.